Compressed Loads

[mookmanjdj]

Last night I loaded some 338 Win Mag bullets with three different loads for testing. Two of them were compressed loads and I could hear the powder crunching down. I have never built or shot a compressed load before, so do I need to watch out for anything or am I taking too much of a chance? I am following some decent data that says compressed load, like I said, I have never tried this before. Any help would be well appreciated. Thanks.

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[nwbobber]

I have loaded .338 compressed loads with good results. I believe it is safe if you are using reliable data. Not everything on the net is reliable, and not everything in (some)reloading manuals is reliable either. Usually the compressed loads are worked up from lower charges that are not compressed, and I work up very gradually at the upper end with all my rifle loads. Many times the best load with a powder is not max. What is your load?

 

[deadeye]

Did it state in the book that it was a compressed load? I have reloaded this type in 300 mag. and the only issue I have noted is the primer pocket will sometimes become oversized to the point of being non usuable.

 

[mookmanjdj]

I have loaded .338 compressed loads with good results. I believe it is safe if you are using reliable data. Not everything on the net is reliable, and not everything in (some)reloading manuals is reliable either. Usually the compressed loads are worked up from lower charges that are not compressed, and I work up very gradually at the upper end with all my rifle loads. Many times the best load with a powder is not max. What is your load?

I am testing a Nosler Accubond 250 gr. My test loads are IMR 4350 @ 69,70,and 71 gr.

 

[deadeye]

Speer book says 69gr max for that combo.
IMR says 69.5gr max

Are you sure you are looking at 300mag and not ultra mag info?

 

[mookmanjdj]

Speer book says 69gr max for that combo.
IMR says 69.5gr max

Are you sure you are looking at 300mag and not ultra mag info?

338 Win Mag.

 

[2506]

Might want to take a look at your seating depth. My 338 Win mag load is 75gr of H4831 over a 250gr SBT and it's not compressed.

 

[mookmanjdj]

Might want to take a look at your seating depth. My 338 Win mag load is 75gr of H4831 over a 250gr SBT and it's not compressed.

3.400" OAL. What is yours?

 

[2506]

3.400" OAL. What is yours?

3.530" COL.

 

[Jamie6.5]

Might want to take a look at your seating depth. My 338 Win mag load is 75gr of H4831 over a 250gr SBT and it's not compressed.

http://www.tacticoolproducts.com/powder.pdf <This table includes VMD and density.

IMR4831 and H4831 are different powders.
The density of H4831 is higher than IMR4831, so IMR will take up a bit more room @70 grains.
Then there's bullet design,...

 

[2506]

http://www.tacticoolproducts.com/powder.pdf <This table includes VMD and density.

IMR4831 and H4831 are different powders.
The density of H4831 is higher than IMR4831, so IMR will take up a bit more room @70 grains.
Then there's bullet design,...

I think the IMR is a faster powder as well. With 250gr bullets, you may want to reconsider your powder choice as well.

 

[nwbobber]

You said 4350 right? My speer book maxes out at 69 gr, Nosler 68 gr with 250 gr bullet. I used to load 69 gr in mine with the 250 partition and got something close to 2700 fps. That is a good load, but I wouldn't push it further. Compressed loads in the .338 are done with slower powders, like RL22 and IMR 7828. I have no data for a compressed load in the 338 winchester mag with IMR4350.

Your OAL is over saami spec, so I assume you have measured this load in your chamber, and it is off the lands a bit. If not you could have pressure issues from that also. I had a remington that had a long throat, and I loaded kind of long in that rifle, My present .338 would not chamber those.

 

[2506]

My loads are built to the rifle, not SAAMI, as they should be otherwise you're missing out on some accuracy/velocity possible gains. The load I described is very accurate and goes consistently at 2850 fps. That little extra has more to do with the addition of a custom barrel than anything else, in my opinion. All of my rifles with aftermarket tubes enjoy a couple extra fps than factory.

 

[deadshot2]

On Compressed Loads in general, sometimes a load workup will result in the heavier charges resulting in a "crunch" when seating. These loads may not be listed as "Compressed".

What is usually the situation is that the powder is loosely packed in the case when just poured in. When using charges that approach the usable volume limit of the case it's often best to use a drop tube which will cause the powder charge to fill the case in a more tightly packed state.

I built a simple drop tube using a 8" piece of brake line from my local auto parts store. It was flared on both ends with flare nuts. I cut the flare off one end, removed both nuts, then J-B Welded the tube into the end of an inexpensive Lee Powder Funnel.

The remaining flare fits just right over the case mouth and the powder is spread out to flow more "granule by granule" into the case.

This makes many "crunchy loads" for my .308 just like normal with no compressing of the powder. Not really necessary for ball or short-cut powders but almost essential for the extruded "rat droppings" like Varget, H-4895, etc.

Just take a case that you will be loading along with you when selecting a piece of tubing. Select one that the case mouth fits into the flare but the ID of the tube is slightly smaller than the case neck ID. You'll have your "Drop Tube Funnel" ready to go by the next morning.

 

[mookmanjdj]

I did a little stepping back. I decided to change to 68, 69, 70gr loads. I have tried these bullets at 66gr with poor results so I hope i'm heading in the right direction. I enjoy trying to figure it out so I'll post my results soon. I can't thank you guys enough for such valuable information. I love to interact on this site. God bless you all.

 

[nwbobber]

2506 did you put on a longer tube? Wondering how you are getting more velocity. I agree about the seating depth by the way, I do all mine that way, just don't want to assume everyone knows that on the 'net'.

 

[2506]

2506 did you put on a longer tube? Wondering how you are getting more velocity. I agree about the seating depth by the way, I do all mine that way, just don't want to assume everyone knows that on the 'net'.

24 inches, nothing more.

 

[chainsaw]

My Savage 338wm likes 72 grs of IMR4831,I can just hear a little crunch when seating 250 gr.partitions.I worked up in half gr.incriments until I started to see signs of over pressure,hard bolt opening in this instance,and backed off a little.I can get 5 or 6 loadings before the primer pockets start to loosen up.

 

[Silver Hand]

I Hunted for over forty years with the .350 Rem Mag., Short Action .35 Cal. - using 250 grain Speer Spire points or 250 grain Rem. SP Core lokt that were pushed into the powder about a quarter of an inch. Follow the book correctly and things will work out fine.
Silver Hand

 

[mookmanjdj]

Ends up that 70 gr of IMR 4350 was the best load. I'd say it was compressed a little anyway. I got about a 1" group at 100 yds. Thanks for all the info.