reading pressure signs

[Spitpatch]

"Even the Nosler load data achieves this with 2.5gr less powder in fact."

This is precisely what Dave from Twisp was trying to bring to attention. 2.5 grains ABOVE NOSLER MAXIMUM is a very dangerous country. Prohibitive to me even at first glance.
You are wasting your time trying to redeem this load through "adjustments". If your luck holds, you may get away with only destroying the rifle.

As to .25-06 barrel life, I've owned one ever since the first year it was a commercial cartridge. That was a 700V (fat barrel). After shooting the bejesus out of it, I traded it for a pickup truck (and it showed no signs of "wearing out").

I now have a Winchester M70 XTR and a Browning 78 (single shot). The Browning has been with me over 40 years. The only barrel issue is one that I am solely responsible for: I wounded an Antelope, which required that I load and shoot the 78 as fast as I could while he ran, finally caught him with shot number 8 or 10 at about 600 yards. The barrel was nearly stove-burner hot.

I can detect "frosting" in the throat with my naked eye. I know it happened on that day. The gun still shoots like it did when new.

With proper care and severe attention to cooling between shots (staying out of Prairie Dog Towns with it), a .25-06 barrel should last a lifetime.

 

[BigGame]

4 sets of 6 rounds at .005" seating depth increments all averaged about 3040fps. I found it interesting the velocity didnt have a slight increase as the seating depth increases but clearly the pressure signs favored the -.015 and -.020 depts (from the lands).

Your velocity is around max as well, so that's consistent with all of the cautions you're hearing.

Regarding the case head separation, something to check. You say you're only bumping the shoulder back a small amount (not sure if you mentioned how much). Measure the base to shoulder dimension of those cases that have now been fired three times. Is it the same dimension you've found before and set your dies to? I ask because cases typically are not fully fireformed after the first firing. They may continue growing a bit through the second and even third firing. If you set your shoulder bump off of the first firing, you may subsequently find that when you thought you were only bumping the shoulder 0.002 you were in fact bumping it substantially more than that. Excessive resizing can lead to the headspacing, thinning, and case head separation noted in a number of the prior messages.

I also would reiterate checking the bore for any evidence of a carbon ring or fouling build up. Investing in a Teslong borescope might be worth it.

 

[leverite]

In addition to reducing your powder load, try neck sizing.
No reason to FL size is there?

 

[tac]

Agreed, if you are only shooting that cartridge in the one rifle.

 

[orygun]

Go back to the Nosler book for your Nosler bullet. Your .25-06, even with warm loads should provide 5 to 10 reloadings per case. If you are financially comfortable, 5 cycles is my general limit for highpower rifle brass loaded warmly each time. Friends tell me I am throwing away good brass.

I always start with the bullet maker's data if possible, and I've not found Nosler's data all that "soft". My copy of their #6 manual shows 52gr of IMR4831 as max for this combo, so the OP is "only" half a grain over Max. I also wonder, is the chamber a bit long for the case after running through the FL die? This type of failure is/was widely seen in the British 303 due to fully resized brass and long chambers. If a case has excessive headspace and is loaded hot I'd expect it would last a time or two before it had case head separation. @Spitpatch mentions reusing cases 5-10 times and I concur based on my fairly hot 30-06 loads.

I think there's a headspace issue.

 

[Spitpatch]

Wouldn't be the first time someone waved a "6" around while I packed a "7".

Orygun (despite personal inadequacies in at least the area of loading manuals ), has commendably stumbled on some VERY pertinent information.

Nosler, in their #7 manual has seen fit (we may assume for VERY GOOD REASONS) to modify their load for the Partition and IMR4831. As pointed out, the modification is more than a "shave". It is indeed a reduction of two grains. (at 50 MAX).

SOMEBODY at Nosler was made aware (either by testing or repeated reports from the customer base) of the specific and identical issue Koda ran into head-on (and fortunately survived to tell us about). We might speculate that the test gun producing the 52.0 was more forgiving than most, but even my Nosler #4 shows the same "Wiseman barrel, 24" (as in #7).

Interestingly, #4 (what I carried at a less developed time of my life) also shows the max load as 52.0.

Manuals indeed are often in conflict with each other. Even from the same manufacturer, they can show disparities as testing is repeated with different results. I have some old Speer manuals that show loads hotter than a branding iron. Ackley's book is infamously scorching.

However, Orygun has brought to light one of the most dramatic shifts (especially in sequential manuals from the same company) I have ever seen.

Such a sudden and dramatic shift should receive ALL our attention (and a healthy measure of prudent caution).

52.0 grains is too hot, as Nosler eventually discovered. Loading manuals include no guarantees. In fact, each one is published with a precise opposite.

 

[daved20319]

Wouldn't be the first time someone waved a "6" around while I packed a "7".

Orygun (despite personal inadequacies in at least the area of loading manuals ), has commendably stumbled on some VERY pertinent information.

Nosler, in their #7 manual has seen fit (we may assume for VERY GOOD REASONS) to modify their load for the Partition and IMR4831. As pointed out, the modification is more than a "shave". It is indeed a reduction of two grains. (at 50 MAX).

SOMEBODY at Nosler was made aware (either by testing or repeated reports from the customer base) of the specific and identical issue Koda ran into head-on (and fortunately survived to tell us about). We might speculate that the test gun producing the 52.0 was more forgiving than most, but even my Nosler #4 shows the same "Wiseman barrel, 24" (as in #7).

Interestingly, #4 (what I carried at a less developed time of my life) also shows the max load as 52.0.

Manuals indeed are often in conflict with each other. Even from the same manufacturer, they can show disparities as testing is repeated with different results. I have some old Speer manuals that show loads hotter than a branding iron. Ackley's book is infamously scorching.

However, Orygun has brought to light one of the most dramatic shifts (especially in sequential manuals from the same company) I have ever seen.

Such a sudden and dramatic shift should receive ALL our attention (and a healthy measure of prudent caution).

52.0 grains is too hot, as Nosler eventually discovered. Loading manuals include no guarantees. In fact, each one is published with a precise opposite.

Good call, Spitpatch. This is one of the reasons I check out online resources rather than just relying on possibly out of date paper manuals. Technology improves, bullets get redesigned, powders get reformulated, any or all of the above could explain Nosler's shift in max load in this particular instance. I have 2 Hornady manuals, 9th is paper, 10th is an e-book. I ordered the latter because I was using bullets in my 6.5 CM that were released after the 9th edition was published. I do agree with Orygun, though, my first source preference is bullet manufacturer, followed by powder manufacturer. I do have Lee and Lyman, but they get used as backup data rather than primary.

I'm still curious about some of Koda's process. He keeps referring to OAL as some distance off the lands, without ever actually saying what his OAL is, either base to tip or base to ogive. I think he's possibly confusing himself, I know it confuses me. I'm also curious exactly how he determined his headspace, even with a hot load, getting a case separation after only a couple of loadings seems excessive. It might be enlightening, for Koda and us, if he listed the tools he's using and how he uses them. And if this has already been covered, my apologies, I haven't caught up on all the posts yet. Later.

Dave

 

[orygun]

Nosler, in their #7 manual has seen fit (we may assume for VERY GOOD REASONS) to modify their load for the Partition and IMR4831. As pointed out, the modification is more than a "shave". It is indeed a reduction of two grains. (at 50 MAX).

SOMEBODY at Nosler was made aware (either by testing or repeated reports from the customer base) of the specific and identical issue Koda ran into head-on (and fortunately survived to tell us about). We might speculate that the test gun producing the 52.0 was more forgiving than most, but even my Nosler #4 shows the same "Wiseman barrel, 24" (as in #7).



52.0 grains is too hot, as Nosler eventually discovered. Loading manuals include no guarantees. In fact, each one is published with a precise opposite.

Maybe this is why we're always supposed to start low and work up.
I have Nosler #2 and #3. Both say Hart barrel, with #2 further noting Remington 40X action. Between #2 and #3 the Partition gained weight and changed shape, but the charge weights remained the same at 52gr.

 

[tac]

Unless you have a headspace gauge set, there is no way that a non-gunsmith can check the headspace.

Fixing excessive headspace is not something to be taken lightly. The designers of the Lee-Enfield rifle, way back when, had the foresight to make interchangeable bolt heads in increasing lengths to accommodate inevitable chamber wear, until, having reached the end of the line, the rifle had the barrel changed and the whole process began again.

AFAIK, nobody else has EVER copied this astonishingly innovative idea. Most 'fixes' involve setting back the barrel in the action, and re-chambering - usually $$$$$$$$$$$. The Lee-Enfield fix costs around twenty bucks.

 

[gmerkt]

the pressure signs a symptom of overcharging

Testing the Outer Limits.

some pressure signs, stiff bolt lift, case head crack and extractor impression.

Case head crack = Beyond the Outer Limits, under the circumstances noted.

 

[Koda]

Note: just catching up since Ive been out of town scouting for elk season the past 4 days....

But this has been a good discussion and helping me learn. The 2gr reduction in the Nosler load data is valuable information to understand. Ive been going by the Lee Modern Reloading 2nd edition... which currently list this load at 53gr max. As someone new to reloading I assumed if I stayed within the range of any published data I would be fine. I will no longer trust load data, a guide only at best that someone achieved with some combination of barrel, chamber, brass and other elements that most likely anyone else will ever match precisely. I will be starting over with my recipe from the bottom, working my way up to a respectable safe velocity that does not show any pressure signs. Unfortunately this means I wont have my hunting recipe for this season, but thats ok... first world problems. I have a good zero with a respectable factory load from Hornady, and can take my time load developing for next year.

Highly appreciate all the replies...

 

[BigGame]

I'm sorry if you won't be able to use a hand load this season. I also appreciate the great openness you demonstrate to hearing what others have to suggest. You set a good example.

A final comment on the case head separation. This is not a typical pressure sign. It's great that you're going to work up a new load, but please take note of the several comments specific to case head separation in this thread. This is not simply an overcharge symptom. You're well on your way to re-tuning the charge, but you also need to pay attention to why you got a case head separation. Lots of comments on this above. Solve it and you'll be shooting those cases 10+ times before they wear out.

 

[Koda]

I'm still curious about some of Koda's process. He keeps referring to OAL as some distance off the lands, without ever actually saying what his OAL is, either base to tip or base to ogive. I think he's possibly confusing himself, I know it confuses me. I'm also curious exactly how he determined his headspace, even with a hot load, getting a case separation after only a couple of loadings seems excessive. It might be enlightening, for Koda and us, if he listed the tools he's using and how he uses them. And if this has already been covered, my apologies, I haven't caught up on all the posts yet. Later.

I'm measuring the cartridge from the base to ogive using a Hornady gauge. I also measure the chamber by the cartridge base to the lands using another Hornady gauge. I'm using a Redding full length sizing die but I use their Competition shell holders to minimize shoulder bump just enough to make a fireformed case easily chamber. I'm wondering now if that has something to do with the short life of the case separation....

 

[gmerkt]

I will no longer trust load data,

Trust it at starting levels. And work up from there. Jumping ahead and starting at max. levels can lead to the kinds of problems you've mentioned. The many reloading books vary, online data varies. Even Hodgdon online data isn't always reliable. I've used a couple of Hodgdon recommendations at minimum levels that, in my particular firearms anyway, turned out to be quite hot.

I will be starting over with my recipe from the bottom, working my way up to a respectable safe velocity that does not show any pressure signs.

This is the preferred method.

I have a good zero with a respectable factory load from Hornady, and can take my time load developing for next year.

In this matter, slow and easy wins the race.

 

[Spitpatch]

"As someone new to reloading I assumed if I stayed within the range of any published data I would be fine. I will no longer trust load data, a guide only at best that someone achieved with some combination of barrel, chamber, brass and other elements that most likely anyone else will ever match precisely."

If the publishers of load books were not so concerned with legal jargon to keep their fannies out of hot water, this rendition would describe the purpose of loading manuals perfectly.

" It's great that you're going to work up a new load, but please take note of the several comments specific to case head separation in this thread. This is not simply an overcharge symptom."

I would grant the POSSIBILITY that "this is not simply an over charge symptom", but if the implication is that head separation cannot occur in a situation restricted ONLY to overcharge, that implication is not only wrong, it is dangerous.

Koda has been unusually meticulous in every aspect of his load assembly. His gun is (for all practical purposes) near new and of top-drawer manufacture. We have now Nosler's own dramatic adjustment recognizing an overcharge problem DID exist with THIS SPECIFIC BULLET, POWDER, CHARGE WEIGHT and CARTRIDGE.

On the other hand, we have no hard evidence at all (or for that matter any reason to believe) that any headspace problem exists with this gun, or that Koda's loading technique is lacking in ANY aspect.

The .25-06 is a racehorse of the first order, and just as tempermental. In my own experience with it (and IMR4831: my favorite for it), unusual things happen at the top end of charge weights. It in fact is also the "poster child" cartridge of cautions against reduced loads, and the dangerous anomalies that can happen with that.

The problem will go away with a reduction in powder charge to a point BELOW the new recommendation, approaching the "new max" cautiously, and continuing the admirable attention to detail in assembly as before. If velocity is the end-game indispensable goal, a bullet of different manufacture (creating less pressure) may be advisable.

I'd end up throwing 49.5 grains behind that Partition and go punch an elk. Pick up your perfect brass from your excellent gun and get to work. The elk will remain speechless at your load's performance, unconfused by any load book.

 

[daved20319]

I'm measuring the cartridge from the base to ogive using a Hornady gauge. I also measure the chamber by the cartridge base to the lands using another Hornady gauge. I'm using a Redding full length sizing die but I use their Competition shell holders to minimize shoulder bump just enough to make a fireformed case easily chamber. I'm wondering now if that has something to do with the short life of the case separation....

For the sake of clarification (and my OCD ), I'm going to put names to these various tools just to be sure we're all on the same page. First up is the Hornady Bullet Comparator, which has a couple of uses. Used in conjunction with the Hornady OAL gauge (formerly Stony Point), it's used to locate max seating depth to the lands. Used on its own, it's used to set and verify seating depth.

Switching to the Hornady Case Comparator, it's used to determine shoulder bump, and then set your resizing die and verify dimensions.

One important point to remember with ALL these tools is that they're used to determine relative numbers in YOUR particular rifle, with YOUR particular set of calipers. In other words, you're comparing (Comparator) a fired case from your rifle to something else, maybe a factory round, maybe a case fresh out of the resizing die. Either way, those numbers only apply to YOUR particular application, someone else might get different numbers with a different gauge and caliper, even though they're working with the same rifle.

One last note and an apology. Again, not trying to nitpick, Koda, but a fire-formed case is one that's been fired in your rifle but NOT resized, or possibly just neck sized. Cases treated this way tend to have a longer life span, but will likely only work in your specific rifle. And they'll still need full length resizing after a few rounds of neck only sizing. A full length resizing die is designed to bring that case back to SAAMI minimums on the theory that it will then work in any rifle chambered for the same cartridge. The Competition Shell Holder sort of falls between these two extremes, I use them too and like them.

Finally, the apology, guys. I'm sorry if this feels like I'm beating a dead horse, but terminology and tool (mis)use has messed up plenty of us at various times. Also sorry if I'm excessively long winded, but we're discussing a precision (hopefully) activity here, being precise in our language is all part of it IMO. Hope I'm at least a little bit helpful, later.

Dave

 

[Koda]

I'd end up throwing 49.5 grains behind that Partition and go punch an elk.

Its interesting as this is what I was thinking of, though will still work up to this as a first test. I probably wont get this before elk season as I ramp up scouting my deer hunt in sept.
I just got back last night from 2 days on foot scouting elk in a huge road closure area were packing into on foot, we found a beautiful timber area dispersed with pocket meadows up to 200yds across (laser) which is perfect range for my 25-06. Lots of sign and saw the first elk rub of the year. (All the bulls we saw are still in velvet).Above us is a high country alpine basin loaded with elk sign as well. Unfortunately we only have spike tags this year but it will be fun no matter if not sucessful.

I look forward to taking my time developing this partition load over the next winter and year for 2022. Once I settle on a final recipe I want to compare the velocities between winter and summer temps then order a CDS dial for my Leupold for this partition...

I shoulda got into this reloading many years ago.

 

[Koda]

Finally, the apology, guys. I'm sorry if this feels like I'm beating a dead horse, but terminology and tool (mis)use has messed up plenty of us at various times. Also sorry if I'm excessively long winded, but we're discussing a precision (hopefully) activity here, being precise in our language is all part of it IMO. Hope I'm at least a little bit helpful, later

No worries your fine to point out the terminology and I appreciate learning the proper terms. I simply forgot the names of the gauges since I threw the packaging away but you listed what Im using.
I wish I had the time to type all the details of my process and the hours ive spent measuring cases at various firings, including factory ammo... To check my consistency and compare to factory. Im typing from my phone half the time.

 

[Spitpatch]

I was wondering what your purpose for this load was. (Elk is precisely what I was hoping to hear.)

I have played a bit with heavier bullets (over 100gr) in the .25-06, but for my purposes (deer and antelope), the 100grain bullets have done it all and VERY well, even on stinky old silver-faced fat Muleys. My early favorite bullet was a Sierra Soft Point Boat Tail, but when Ballistic Tips hit the stage, I never looked back.

As noted before, I DID have to sacrifice a shade of velocity going to this long-for-weight bullet (I was hot on the heels of Weatherby velocities with the Sierra), but the accuracy was worth the trade.

DO NOT discount the integrity and killing power of bullets other than the Partition. Yes, I would stick with the heavies (115-120) for elk, but I would not restrict myself to the Partition. Most bullets .257 in that weight range are indeed Big Game bullets, and of stout construction (thick jackets, etc.). Your velocity goals may be easier to reach as well.

Having shot and seen others shoot lots of game with Partition bullets, I have noticed that with ribcage impact (and no other bones hit), more often than not the game WILL travel after the shot, and sometimes with little indication of the hit. They DO die, but the "shock" effect (as compared to other bullets landing in the ribcage) is not great. On an angular shot where one wants large bones at the other side of the animal penetrated, the Partition may have no equal, save for those of monolithic (all copper) construction (my extensive trials with those in other cartridges...and I WANT them to work...was less than satisfactory where accuracy was concerned. Also, pressure issues due to their construction...sound familiar?... came to bear).

With the Partition, what you have (using a 120g .257 as an example) is basically a 60 grain light jacket softpoint smacking your animal, immediately followed by a 60 grain heavy-jacket Solid right on its tail. Partitions (when they are occasionally recovered) rarely exhibit the expansive double-diameter-or-greater mushrooms seen in many other recovered bullets. Rather, the rear section with the front jacket peeled back tightly over it (the front portion of lead core is almost always non-existent), is of a diameter not greatly larger than original. (In .257 the mushroom face might approach .30-35 caliber.) This is GOOD for penetration and breaking bones. Not so good for large wound channels and rapid hemorrhage.

I want my bullet to expend all (or nearly all) its energy in the animal. I prefer my bullet to "keep working" while it travels inside the animal, continuing to expand as long as such expansion does not impede penetration to the other side of the animal. Exit wounds are of value, but not at the expense of significant wasted energy that should remain inside the game. The very attribute of a Partition bullet is that it has an "off-switch" for expansion.

In a .25-06 intended for elk, the Nosler Partition would certainly be at the top of my list of bullets to try. I would not allow it to be my only choice.

As example, my chosen bullet for the .270 Winchester that has worked instantly on elk every single time, is the 150grain Ballistic Tip. A big Bob Marshall Wilderness 6-point took one at a dead run at 175yards. It entered the BALL of his leading shoulder, and exited out the shoulder blade of his far shoulder, breaking both. He nose-dived into ten inches of snow and was still.

The rear of the jacket on this bullet is stout. It has that solid copper disk that makes up the boattail, and holds on to some jacket. It is of inordinate length, supplying it with the same characteristic of penetration combined with steady work inside that makes the 6.5x55 such a great "elk" (read: "moose") caliber in Sweden.

Not sure 115gr Ballistic Tips (or 110gr Accubonds) would be well-received as a recommendation for elk in the .25-06, but they'd sure get taken for a spin in any of my experiments (along with others).

 

[Koda]

I was wondering what your purpose for this load was. (Elk is precisely what I was hoping to hear.)

I have played a bit with heavier bullets (over 100gr) in the .25-06, but for my purposes (deer and antelope), the 100grain bullets have done it all and VERY well, even on stinky old silver-faced fat Muleys. My early favorite bullet was a Sierra Soft Point Boat Tail, but when Ballistic Tips hit the stage, I never looked back.

As noted before, I DID have to sacrifice a shade of velocity going to this long-for-weight bullet (I was hot on the heels of Weatherby velocities with the Sierra), but the accuracy was worth the trade.

DO NOT discount the integrity and killing power of bullets other than the Partition. Yes, I would stick with the heavies (115-120) for elk, but I would not restrict myself to the Partition. Most bullets .257 in that weight range are indeed Big Game bullets, and of stout construction (thick jackets, etc.). Your velocity goals may be easier to reach as well.

Having shot and seen others shoot lots of game with Partition bullets, I have noticed that with ribcage impact (and no other bones hit), more often than not the game WILL travel after the shot, and sometimes with little indication of the hit. They DO die, but the "shock" effect (as compared to other bullets landing in the ribcage) is not great. On an angular shot where one wants large bones at the other side of the animal penetrated, the Partition may have no equal, save for those of monolithic (all copper) construction (my extensive trials with those in other cartridges...and I WANT them to work...was less than satisfactory where accuracy was concerned. Also, pressure issues due to their construction...sound familiar?... came to bear).

With the Partition, what you have (using a 120g .257 as an example) is basically a 60 grain light jacket softpoint smacking your animal, immediately followed by a 60 grain heavy-jacket Solid right on its tail. Partitions (when they are occasionally recovered) rarely exhibit the expansive double-diameter-or-greater mushrooms seen in many other recovered bullets. Rather, the rear section with the front jacket peeled back tightly over it (the front portion of lead core is almost always non-existent), is of a diameter not greatly larger than original. (In .257 the mushroom face might approach .30-35 caliber.) This is GOOD for penetration and breaking bones. Not so good for large wound channels and rapid hemorrhage.

I want my bullet to expend all (or nearly all) its energy in the animal. I prefer my bullet to "keep working" while it travels inside the animal, continuing to expand as long as such expansion does not impede penetration to the other side of the animal. Exit wounds are of value, but not at the expense of significant wasted energy that should remain inside the game. The very attribute of a Partition bullet is that it has an "off-switch" for expansion.

In a .25-06 intended for elk, the Nosler Partition would certainly be at the top of my list of bullets to try. I would not allow it to be my only choice.

As example, my chosen bullet for the .270 Winchester that has worked instantly on elk every single time, is the 150grain Ballistic Tip. A big Bob Marshall Wilderness 6-point took one at a dead run at 175yards. It entered the BALL of his leading shoulder, and exited out the shoulder blade of his far shoulder, breaking both. He nose-dived into ten inches of snow and was still.

The rear of the jacket on this bullet is stout. It has that solid copper disk that makes up the boattail, and holds on to some jacket. It is of inordinate length, supplying it with the same characteristic of penetration combined with steady work inside that makes the 6.5x55 such a great "elk" (read: "moose") caliber in Sweden.

Not sure 115gr Ballistic Tips (or 110gr Accubonds) would be well-received as a recommendation for elk in the .25-06, but they'd sure get taken for a spin in any of my experiments (along with others).

I find it interesting you were hoping to hear this was an elk load.... Most people agree its too light for elk. Ive considered other bullets for this... But ive also always felt this caliber was/is too light for elk. Hence favoring the partition and at least 3000fps. Im not certain now I can get 3k with this powder but should get close enough.
I inherited this from my dad, when he retired from hunting he sold his 7mm mag without telling me. I claimed this one before he sold it. Its my only big game rifle besides my 3030...
I could buy a new elk rifle but then this one will almost never get used. Ive studied this calibers limitations on elk in length, and satying inside it... Ive taken 4 bulls with it so far all 1 shot. Ive passed on one elk at maybe 400yds... Tag soup that year. Broadside double lung shots are good, same for close range neck shots... Its the quartering away shots and heavy shoulder bones to avoid at distance. Most shots are 100yds or less, it will drop an elk like a rock no problem.
I have some Barns 100gr ttsx im going to work a load for deer and antelope with after I get the 120gr partition down but will keep the partition for elk. I mostly use my 3030 on deer until I get enough points for a muley tag....