Discrepancies between reloading manuals

[agc91campora]

I am a beginner at reloading, having only worked up 100 rounds total. I had some really good results with those initial rounds, but the more I read and learn, the more I realize how little I know!

A few discrepancies I've noticed and I'm not sure what to make of it.

Trim length for .270 Win 150 grain:
Hodgdon's reloading data says 2.530"
Nosler says 2.540"
Hornady says 2.539".
Does the trim length make a difference? I figure as long as my OAL is accurate (measuring base to bullet's ogive) and I am consistent with what I go with in terms of case trim length, it shouldn't matter??

MAX charge using H4350 for .270 Win 150 grain:
Hodgdon - 49.0
Nosler - 52.0
Hornady - 57.6

49.0 - 57.6 grains seems like a significant spread. I assume there is a variable I'm missing here to account for this difference? Again, I'm new to this, so I don't want to experiment with maxing my charge by relying on simply watching for signs of too much pressure on the case. I'll have to learn that part later with experience. Thanks!

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[WillametteWill]

Welcome to reloading! Yes, inconsistent information is normal. I'll put in my $.02 and hopefully you will receive plenty more. Although I stated at it in 1979 with shotguns and followed shortly by handgun loading, still have plenty to learn myself. First the max charge amounts. Commonly newer manuals will have lower max powder charges. There are exceptions but most of my older manuals have very hot max loads listed. Using newer data tends to be more mild...and perhaps safer. Make sure you are comparing the same bullets. Not all 150gr .270's are the same. The max you listed, at about 15% difference, is pretty large. I love my manuals but consider checking the powder manufactures as well. Hodgdon's website has data, for free. (I noticed the 49.0 grains you listed on their site is for a 150 gr. Hornady SP). Not all bullet / powder / round combinations but it's another resource to compare. Other powder companies have similar info on their sites. Looks like you are onto this already.

Others may differ on this but the measurements you listed are pretty minor for me. For 30-30 I find trimming to the same length critical because the cases are not very strong and tend to have issues. Don't tell anyone, but I have never trimmed a .223. I have different batches of 30-30 that vary in length, I just keep them together. I haven't trimmed 30-06 all the time either.

Hope this helps at least a little.

 

[Colts4me]

I like the old Lyman manual that gave factory duplication loads. I checked them with a chrony and they were really close. Then I can go up or down from there depending on accuracy. Once I check the case length to fit the chamber the OAL has to fit the magazine.

 

[agc91campora]

Welcome to reloading! Yes, inconsistent information is normal. I'll put in my $.02 and hopefully you will receive plenty more. Although I stated at it in 1979 with shotguns and followed shortly by handgun loading, still have plenty to learn myself. First the max charge amounts. Commonly newer manuals will have lower max powder charges. There are exceptions but most of my older manuals have very hot max loads listed. Using newer data tends to be more mild...and perhaps safer. Make sure you are comparing the same bullets. Not all 150gr .270's are the same. The max you listed, at about 15% difference, is pretty large. I love my manuals but consider checking the powder manufactures as well. Hodgdon's website has data, for free. (I noticed the 49.0 grains you listed on their site is for a 150 gr. Hornady SP). Not all bullet / powder / round combinations but it's another resource to compare. Other powder companies have similar info on their sites. Looks like you are onto this already.

Others may differ on this but the measurements you listed are pretty minor for me. For 30-30 I find trimming to the same length critical because the cases are not very strong and tend to have issues. Don't tell anyone, but I have never trimmed a .223. I have different batches of 30-30 that vary in length, I just keep them together. I haven't trimmed 30-06 all the time either.

Hope this helps at least a little.

Thanks. That does help. I wondered if different 150 grain bullets would impact the differences for the max charge, but didn't think there would be that much of a spread on bullets alone. What you said about older vs newer manuals makes sense.

 

[No_Regerts]

One thing that can really cause issues is bullet construction. A monolithic bullet with no lead core will be longer than a cup and core bullet of the same length due to density. Longer bullet with more bearing surface changes things.

I generally will start somewhere in the top third of the spread between book minimum and maximum and work up. Some guns deal with pressure better than others.

 

[Colts4me]

Some powders are the same exactly but under different names. You will find that the reloading books give different powder charges even when the powders are the same. Winchester 231 and HP 38 are the same, H110 and Winchester 296 are the same. I believe there is just one powder company making powders for all the names here in the states. Notice at the bottom that IMR, Winchester and Hod are all by the same company.

http://www.hodgdonreloading.com/data/pistol

 

[saxon]

Trim length for .270 Win 150 grain:
Hodgdon's reloading data says 2.530"
Nosler says 2.540"
Hornady says 2.539".

you will also notice they may also list the gun that was used, there is differences between the manufactures of the
bullets they make while they all may be .270 Win 150 grain manufacture variations are abundant and can and do change the way the load will affect each manufactured bullet if you load it to another's listings, perhaps not much but then I have not done bulls eye shooting in for ever so...

 

[gmerkt]

Don't ignore trim length. Rifle cases with shoulders typically grow in length as they are fired. The internal pressure exerted against the inside of the shoulder causes the material to flow forward, the result being the case lengthens and is measurable at the mouth. If you don't trim, what may eventually happen is the case gets long enough that with a bullet seated, it will jam into the leade of the rifling at the end of the chamber. This can result in elevated pressures.

Someone else said they'd never trimmed a .223 case. Decades ago when I first started reloading, .223 were the cases I got in trouble with from not trimming. After establishing a proper bullet seating depth, a long case would come along and the die would slightly crush and buckle it at the shoulder. These rounds wouldn't chamber. .223's are fired at high pressures, yet have fairly thin brass. They grow pretty quickly in length. But I will say, I've picked up fired cases that have been "remanufactured" professionally and sold and had obviously not been trimmed.

One thing I've discovered over the years, reloading is like any other human endeavor, people do it at all levels of skill. If you're gonna do it, why not do it correctly? You don't have to blow serious money on the most expensive case trimming gear. Just get the Lee case length gauge/trimmer, you can chuck that in a DeWalt cordless drill and do it pretty fast, and combine it with the chamfering tool and do that as well at the same time. I like to check brass and loaded rounds with a cartridge headspace gauge, just a machined cylinder with go/no-go lines (Wilson, Lyman, et al). But using the Lee mandrel tool, its design eliminates that need for such a tool if you don't want to spend the extra money on one.

Re. powder charges. I've read the following in several different manuals, and also found it to be true in practice. That is, maximum charges are very seldom the most accurate ones.

 

[agc91campora]

Don't ignore trim length. Rifle cases with shoulders typically grow in length as they are fired. The internal pressure exerted against the inside of the shoulder causes the material to flow forward, the result being the case lengthens and is measurable at the mouth. If you don't trim, what may eventually happen is the case gets long enough that with a bullet seated, it will jam into the leade of the rifling at the end of the chamber. This can result in elevated pressures.

Someone else said they'd never trimmed a .223 case. Decades ago when I first started reloading, .223 were the cases I got in trouble with from not trimming. After establishing a proper bullet seating depth, a long case would come along and the die would slightly crush and buckle it at the shoulder. These rounds wouldn't chamber. .223's are fired at high pressures, yet have fairly thin brass. They grow pretty quickly in length. But I will say, I've picked up fired cases that have been "remanufactured" professionally and sold and had obviously not been trimmed.

One thing I've discovered over the years, reloading is like any other human endeavor, people do it at all levels of skill. If you're gonna do it, why not do it correctly? You don't have to blow serious money on the most expensive case trimming gear. Just get the Lee case length gauge/trimmer, you can chuck that in a DeWalt cordless drill and do it pretty fast, and combine it with the chamfering tool and do that as well at the same time. I like to check brass and loaded rounds with a cartridge headspace gauge, just a machined cylinder with go/no-go lines (Wilson, Lyman, et al). But using the Lee mandrel tool, its design eliminates that need for such a tool if you don't want to spend the extra money on one.

Re. powder charges. I've read the following in several different manuals, and also found it to be true in practice. That is, maximum charges are very seldom the most accurate ones.

Good info. I didn't meant to imply case trimming wasn't important as I will certainly be checking that, but I was curious as to why there where different case lengths mentioned by various resources. I think as long as I stick with one case length and go for consistency, it's probably not as important whether I choose to trim cases to 2.530 vs 2.540?

Thanks for the tip and recommendation on the Lee case length trimmer. I saw those at the store the other day and was thinking about trying one.

 

[Spitpatch]

Case trimming is important not only for function within the mechanism/chamber of the gun, it is equally important for consistency cartridge to cartridge. Consistency is the cornerstone of accuracy. While even some careful handloaders do not engage all minute practices that benchresters employ toward cartridge consistency, trimming cases to precise matching length contributes greatly to neck tension consistency: an important factor in accuracy. Case trimming to the "trim-to length" (as opposed to "maximum case length") early in the life of the brass is a relatively easy (admittedly time-consuming) step that contributes measurably. If all brass is of the same manufacturer (preferably the same lot), is trimmed early in its life and measured during the case prep procedures along the course of its life, a significant variable is eliminated.

If fired in the same gun with comparable loads, the attentive handloader will notice that this little brethren of matching cases stretches quite consistently amongst each other, and the point at which they all need trimming again will be easily detected within the lot.

Variables are the enemy of accuracy. This one we can deal with directly. Do it.

On the other hand, if you choose to be a reloader rather than a handloader, skip this step and more quickly turn your money into noise to great satisfaction.

 

[41mag]

OP:
you're asking some good questions; my goal since circa 1980 has been to learn to reload accurate enough ammunition without getting my head blown off due to some foolish mistake. For myself, the Ballistic realm of reloading is composed of both an Art & a Science.

As example, the measurable Science part of reloading for a Colt 1873 gen 1 revolver, involves the steel/powder/fabrication of all components to a given spec. The Art is the unknowns/unmeasureable interface between (YOU) putting them all together for safe/effective/pleasurable use thereof.

re: "A few discrepancies I've noticed and I'm not sure what to make of it."

given there are differences in the published trim length specs; in my own practicality, it is damn hard to make consistent measurements of 0.01" regardless of my time & effort to do such.

Further, I've discovered and remain satisfied I don't have the personality characteristics of a OCD benchrest precision reloader.

Powder charge differences: the vast majority of my reloading is cast lead revolver calibers. I've learned the advantages of avoiding the extreme ends of the reloading recipes, as those extremes are usually where troubles develop. Commonly for my range use, differences of 0.1g whatever powder is of no measurable significance.

Depending on such variables as PSI, 'safe' loads have more to do with those measurable factors any of the reloading books will discuss at length. Those 'more accurate' loads not only accommodate SSAMI specs, but a wide range of independent co-variables that are largely immeasurable from shot to shot.

The needs of a slow fire 100 yard precision benchrest rifle discipline are not the same as a 30' rapid fire pistol match.

Coming to recognize the potential risk in the difference between 0.010 vs 01.00 anything in reloading requires vigilance and continual study.

Good luck. Enjoy!!!

 

[tac]

I reload the following calibres -

Two different .308Win loads for two rifles for different purposes.

Two different 7.5x55 Swiss loads - one for me, that nigh-on duplicates GP11 [Thanks Leon] and one for range guest day shooters so they don't get put on their a$$.

Two different 7x57 Mauser loads - one for my Boer War carbine [stiff, to say the least, with a 200gr RN], and a 175gr FMJ for the more modern [1912] Model B Sporter.

Three different .45-70 Govt loads - one 300gr softie load for range guest days, one .405gr intermediate for up to 600 yards, and a duplicate of the factory .405gr load for longer ranges.

One 6.5x55 SE that's about the same as the original 139gr Service load.

One .38 Spec in .357 Mag cases and one full-house .357 Mag load for long range - both using the 158gr FMJ.

I measure the length EVERY case, and trim it EVERY time I reload to the original factory specs for that brand of ammunition, invariably Norma [except for the Swiss and .357 Mag], although I often find that some I check don't need it.

Result is that my cases last a looooong time. My 7x57 cases are on their seventh reload as I speak.

tac

 

[agc91campora]

Variables are the enemy of accuracy. This one we can deal with directly. Do it.

Makes sense and I totally agree. Now I need to focus and learn how to be consistent!

 

[HB of CJ]

Check the publication dates of the various manuals. Sometimes data gets reduced or watered down to satisfy the legal department. Potential lawsuits from potentially dangerous reloading date. But sometimes the older data may be more significant. Some guns need full power.

The USGI .30 Carbine is an example. The old factory military load was 15.0 grains of H110. The little military light rifle has some quirks. One of them is the need for full power or near full power hand loads. A very slightly tapered straight wall case head spacing on the case rim.

Full pressure loads are needed to seal the brass against the chamber wall plus providing the necessary cycling energy. Carbines are also tricky about overall case length. Too short is bad but much better than too long which can be very dangerous. This is because ...

The Carbine was a War Time platform. This means some safety issues were side stepped. What this means is that all the parts inside the M1 and particularly the M2 must work properly. Not much room for worn out stuff. Thus the need for exactness with the hand loads.

Thus the need for accurate data inside the hand loading manuals. Today it is hard to find published stuff pertaining to the USGI M1 Carbine. Most of the accurate data is old stuff. The .30 Carbine is just one example. Other examples of confusing data exists. A fun steep learning curve.

 

[Spitpatch]

Makes sense and I totally agree. Now I need to focus and learn how to be consistent!

Now you are tracking. The goal of all cases being the same is infinitely more important than an arbitrary (and as you discovered, varying) "trim-to" length published in different manuals. What should be consistent in all manuals (this will incite a bookworm to predictably find an exception) is the SAAMI spec for Maximum Length. Some manuals dispense with "trim-to" length altogether, and only show Maximum Length. Stay under Max and keep 'em all the same.

Warmer loads can increase case stretching, arriving at Max in less firings than milder loads. Generous chambers can contribute as well.
Never do your measurement prior to sizing. Sizing is where some increase in length occurs, so always take your measurement after sizing. You can buy some time toward reaching Max by neck-sizing (or partial sizing), as long as the brass will be fired in the same gun. (This is also a technique that can increase accuracy, as your fired brass is a wonderful perfect casting of the chamber of that gun, and the less we mess with it, the better.) Your bolt may close on the cartridge with a bit more effort (like the airtight bank vault that it has become), so cycle all cartridges prior to an important hunt. Some savvy handloaders who are also serious hunters sacrifice neck sizing benefits in their hunting ammo and will not hunt with anything less than full-length resized (or brand new) brass: they want no cycling hiccups at the moment of truth. I have bought this cheap insurance when on remote hunts. For more domestic adventures I feel cycling ammo thru the gun prior to the hunt is sufficient. So far, so good.

Older manuals can be a valuable resource when they are used IN CONJUNCTION with data from newer sources. If you see an older manual you don't have at a garage sale or gun show, snag it. There may be tasty morsels of "knowledge lost to the ages" in them, even in the narrative portions (apart from the data itself). I never load any cartridge without my gun room floor covered with sprawled manuals (ancient to brand-spanking) open to the pages for the cartridge of interest. You can build a modest sparkling library of manuals for next to nothing.

Knowledge is power.

 

[41mag]

You can build a modest sparkling library of manuals for next to nothing.

excellent advice!

and further riffing off 'Knowledge is power', the combat pistol crowd used to make a big point of the triple-Must-Have related issues :
Diligentia, Vis, Celeritas means Accuracy, Power, and Speed
I've often wondered we haven't come up with a single term that includes all those important points. Perhaps having to use the triad of terms helps us discuss and become aware of the complexity of the subject.

Another point that bears comment in this thread, is the importance of recognizing the difference of between the physical forces affecting the brass on bottle neck vs straight wall cases.

Straight wall revolver brass is less likely to require trim in repeated reloading than higher intensity rifle brass.

Need for trim of even such as 45 acp seems to be of arguable opinions.
In the tens of thousands of acp rounds I've used both in revolver and 1911 frames, there has <almost never> been need for trim for function-fire-reliable factors. Whether better accuracy could have been achieved is speculation. Agree neck tension plays role in performance but have no studies on hand that report metrics supporting my opinion.

Hand gun accuracy at the range requires merging of many related components of that mission.

Agree that the controllable aspects of reloading metrics essential to produce best results. Also agree that 'acceptable results' is subjective term perhaps differing from 'best results'.

In cowboy matches, a common phrase was "No target is too big or too close that you can't miss it". Ringing a 6" steel plate at 20 yards in 5 seconds has different ballistic needs than stacking all your shots into the tiny X ring of a 50' bullseye target in 2 minutes.

Safety first thru application of SAAMI specs makes sense.