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338 Allen Xpress, RL33 load development

 
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  #113  
Old 10-08-2013, 09:39 AM
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Re: 338 Allen Xpress, RL33 load development

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Originally Posted by MMERSS View Post
Mark,

My OAL is 3.9" right now with .008" jump. Close to what you are asking. In about three more days I should have more data. 100gr is no problem with pressure signs and will be working up from here.
Just about what we were estimating it would be. Thanks for the information. One less thing I have to try to remember to do today!!!
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

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  #114  
Old 10-08-2013, 05:41 PM
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Re: 338 Allen Xpress, RL33 load development

Played a bit more with some experimenting with RL33 again today at lunch. Its been pretty well estabilished that this powder wants heavy bullets seated close to the lands for best consistency.

Today I wanted to play with neck tension to see if it had any effect on velocity results. For a standard velocity, I took five rounds of my regular 300 AX ammo loaded with the 200 gr Accubond and chronoed them. They averaged 3421 fps and had an ES of 22 fps.

Next I took some of my 7mm AM brass, necked it up to 30 cal and bumped the shoulder slightly to fit in my 300 AX chamber. Loaded 5 rounds. I did this because when you take the 338 Lapua down to 7mm, fireform it and then neck it back up to 30 cal, the necks get quite hard and neck tension increases dramatically. These five rounds average 3428 fps with an extreme spread of 26 fps. No real measureable change.....

Next up I took five rounds of the same brass and annealed it so the case necks were very soft. So soft in fact that when I seated a bullet, I could move that bullet with decent finger pressure so the case was JUST offering enough neck tension to hold the bullet in place. These five averaged 3430 fps and has an ES of 18 fps.

In all honesty, I do not see where neck tension has any real effect on velocity consistency with this powder. Should be noted that all loads were seated to 3.635" which is JUST kissing the lands.

I then repeated the same test above but seated the bullet 100 thou off the lands. Here are the results:

Standard 300 AX brass.............3378 fps............78 fps ES
High neck tension brass............3393 fps............83 fps ES
VERY light neck tension brass....3353 fps............105 fps ES

Again, this basically is saying that distance off the lands is the main factor in velocity consistency with RL33.

As mentioned barrel heat has also shown some effect on velocity spreads so I wanted to test this a bit as well. Let the barrel cool all afternoon and then just when I was leaving the shop, I took 10 rounds and shot them through the chrono with roughly 60 seconds between each shot. Here are the results of velocity as the barrel heat increased.

1. 3436 fps
2. 3418 fps
3. 3419 fps
4. 3434 fps
5. 3438 fps
6. 3408 fps
7. 3455 fps
8. 3428 fps
9. 3411 fps
10.3458 fps

As you can see, from a cold and cool barrel, shots 1 through 4 were quite tight with an 18 fps spread. Shots 4 through 8 had a 47 fps spread and shots 9 and 10 were also 47 fps spread. Total extreme spread was 50 fps.

Now, to confirm test, I let the barrel cool outside until it was barely warm to the touch, in the mean time I took cases from shots 6, 7, 9 and 10. These were the two lowest and two highest velocities. I did this just to see if the velocity spreads were a result of these cases and not the barrel heat. Same exact load, shot these four again with 60 seconds between each firing. here are those results

Case 6. 3428 fps
Case 7. 3421 fps
Case 9. 3438 fps
Case 10.3423 fps

Extreme spread for these four cases was a very nice 17 fps, these cases were the widest spread in the previous test but also 4 of the last 5 rounds fired in the hot barrel.

Its looking like barrel heat is certainly causing some effect on extreme spread. Luckily for us big game hunters, this really does not mean anything. In cool or cold barrels it appears that the first 4-5 shots are quite consistant which is far more then we will generally need. Interesting results so far.

Again, appears that RL33 has some unique personality traits but do not think they are bad enough to cause any real problems once we get them figured out and learn how to load for this new powder.
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #115  
Old 10-08-2013, 06:01 PM
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Re: 338 Allen Xpress, RL33 load development

Thanks again Kirby for the work you are doing & sharing
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  #116  
Old 10-08-2013, 07:50 PM
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Re: 338 Allen Xpress, RL33 load development

Thanks AZShooter and Tumbleweed for a starting point for the 230s.

Results from today's range day.

100gr RL-33 loaded to 3.9 OAL with .008" jump.

3240 fps ES 7

I was seeing extractor marks with this short of a jump compared to .038" and no pressure signs. However, the ES was great. Kirby you nailed it. Big bullets close to the lands for pressure consistency.

Tomorrow I will back off in .5gr increments and see what I can come up with.

Does anyone have temperature regression data for RL-33?
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  #117  
Old 10-08-2013, 08:20 PM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by MMERSS View Post
Thanks AZShooter and Tumbleweed for a starting point for the 230s.

Results from today's range day.

100gr RL-33 loaded to 3.9 OAL with .008" jump.

3240 fps ES 7

I was seeing extractor marks with this short of a jump compared to .038" and no pressure signs. However, the ES was great. Kirby you nailed it. Big bullets close to the lands for pressure consistency.

Tomorrow I will back off in .5gr increments and see what I can come up with.

Does anyone have temperature regression data for RL-33?
Nice velocity.... what length barrel?
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  #118  
Old 10-08-2013, 08:31 PM
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Re: 338 Allen Xpress, RL33 load development

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Originally Posted by MontanaRifleman View Post
Nice velocity.... what length barrel?
30"
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  #119  
Old 10-08-2013, 09:31 PM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by MMERSS View Post
Thanks AZShooter and Tumbleweed for a starting point for the 230s.

Results from today's range day.

100gr RL-33 loaded to 3.9 OAL with .008" jump.

3240 fps ES 7

I was seeing extractor marks with this short of a jump compared to .038" and no pressure signs. However, the ES was great. Kirby you nailed it. Big bullets close to the lands for pressure consistency.

Tomorrow I will back off in .5gr increments and see what I can come up with.

Does anyone have temperature regression data for RL-33?
I have only done a very limited amount of testing in different temps and that was with my 7mm Allen Magnum with the 180 gr Berger VLD. This was before I had figured out that velocity consistency was dramatically effected by jump to the lands and in my old 7mm AM barrel, these bullets were making quite a jump to the lands so my information is likely not all that solid.

Still, I had loaded the 180 gr berger up to around 3330 fps in 60 degree temps. Tested them on different mornings, at 30, 40 and one afternoon at 75 degrees.

On the low end, five shots averaged 3308 fps. On the top end, the average velocity was 3356 fps. So in my mind with a 45 degree temp change with the same load, there was a 48 fps velocity spread. If you had developed your load and drops for around 50 degree, there would only be a +/- 24 fps variation for a temp range from 30 to 75 degrees at least for temp change alone.

Now, keep in mind, these results were average velocity levels but the extreme spread of these 5 shot groups ranged from 45 to 80 fps so how much stock I would put on these results is not a great amount but it did show a trend.

Need to test now that I know better how to load this powder and should be able to get more accurate and usible test numbers.
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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