Custom 50cal smokeless muzzleloader - Canada - "Accuracy Development Solutions" - Ken Thiessen

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I would like to try the 385gr Great Plains projectiles. I have N120, but I'm wondering if a slower powder would be better.
I can get some IMR3031 locally, which was documented on the forum as workable for 400gr projectiles in Savage 10ML's. Would it be foolish to start well below the lower loads listed here? (eg 60-65gr 3031 with 385gr projectile.)

With brass cartridge reloading I know that the minimum loads are important, because of the set volume of the brass cartridge. The ratio of powder volume to air volume in the brass cartridge can cause problems when there is too little powder and too much air. Conversely, with a smokeless muzzle loader can I safely load smaller charges given that I'm loading the projectile directly against the powder column? Is that a fair deduction, or is it likely to cause safety concerns?

I have a healthy supply of Varget and RL16 for cartridge reloading. Would it be worth trying powders like these which are slower than 3031? From reading through old posts I'm seeing rather large charge weights of these powders for pushing big projectiles (100+ grains?!).

Maybe this will help some as a guideline to where burn rates apply to different bullet weights. As always this is a guide, you must test in YOUR gun. Start low and work up as with any load development. These loads have been shot in Savage ML's. I do not know how that compares with the ULA. I do know that some are real rompers & stompers in the Savage.

N120
250 grain bullet: 65-69 grains
300 grain bullet: 58-63 grains
350 grain bullet: 58-62 grains


H and Imr-4198: Maximum loads should be reduced by 2 grains if using Imr-4198 the loads listed are for H-4198
250 grain bullet: 65 to 71 grains
300 grain bullet: 64 to 68 grains
350 grain bullet: 64 to 66 grains
400 grain bullet: 60 to 64 grains

Reloader #7
250 grain bullet: 64 to 69 grains
300 grain bullet: 60 to 65 grains

N130
300 grain bullet: 69 to 73 grains
350 grain bullet: 64 to 68 grains

10X
250 grain bullet: 74 to 78 grains
300 grain bullet: 71 to 75 grains

H322
300 grain bullet: 72 to 76 grains
350 grain bullet: 70 to 74 grains
400 grain bullet: 66 to 70 grains

Xmr-2015 (very similar to H322)
300 grain bullet: 73 to 78 grains
350 grain bullet: 71 to 75 grains
400 grain bullet: 65 to 70 grains

Imr-3031
350 grain bullet: 77 to 80 grains
400 grain bullet: 73 to 76 grains
 
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I gave Reloder 7 another try with the H25045SRR sabots, since their tighter fit should create more back pressure. I saw much better results than last time, so the MMP HPH 24 sabots must have been too loose in the bore for reliable combustion of RL7.

Three shots of a very light RL7 load (45.0gr) has matched my best so far with this smokeless muzzleloader at ~2MOA.
300gr SST
H25045SRR
AVG 1458fps
ES 34fps

20221016_183148~2.jpg

Still waiting on my shipment of sabots from prbullets.

I have AA5744 and IMR3031 waiting for me to pick them up this week.
 
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I have tried many sabots, bullets, and powder combinations which performed poorly.
Today I had my first decent group at 50yards:
44.0gr AA5744 with 290gr BORE DRIVER
1667175972604.png
They fit a bit looser than I'd like, and even N120 had inconsistent combustion with a few squibs.
Unfortunately I didn't have enough of these left to repeat the group.
I'm definitely going to pursue these further.

1667176531255.png
 

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