Home Forums Reloading Big Game Rifles Unburned powder in new Marlin barrel

Bought a new Marlin 1895 in 45-70.

Just tried some reduced pressure loads that were mentioned in a Handloader article to start with. Only tried one powder, Varget, with 57 & 58 grains under a 300 gr Remington HP. Also tried 48 & 50 grs under the 405 gr Remington SP.

Got 1 inch group with the 300 gr HP and then groups opened to 1-2 inches. No complaints there. Not sure after which load I noticed it but there were grains of powder unburned in the action of the rifle. Only a few grains here or there. When cleaning the rifle, powder grains were stuck to the inside of barrel. Surprised me when I saw this and was wondering what may be the cause of it? Too slow of powder? Need to use magnum primers?

Using Starline brass and CCI 200 primers.

Any thoughts?

Try RL-15 and/or WLRs.

Use one of the 4198s with 300s; H322 with heavier bullets, or RL7 with any weights. The 4895s are also versatile weightwise - even up to 500 grains. I was not impressed with Varget when I went that way either. Lots of good stuff that doesn't leave action clogging crumbs.

"Unburned powder in new Marlin barrel"

Maybe you need a new barrel?

Naw,just kidding!

Unburned powder is normal with reduced pressure loads with slow (for the purpose) powders. Using light loads of faster burning powders can raise peak pressure while maintaining the low speeds, and makes for a more complete burn.

Mine leaves unburned powder with almost all my loads but it is dead nutz accurate with the 300 gr. BT

Any of you guys tried 2015?

You can try slightly more crimp. The extra bit can hold the bullet just a bit longer and give the primer the chance to burn a bit more of the powder. At least that's what I believe and has worked in my reduced loads. FWIW, I like 26.0 grains of SR4759 with Remington 300 grain JHPs for a chronographed 1279 fps out of a 20" barrel.

Some powders seem to be less sensitive to reaching a certain pressure to burn well without leaving the big chunks. Most powders leave some residue. Varget is a powder which which works very well but seems to need a specific pressure level to really burn well. In a similar burn rate, H322 works across a much broader pressure range, even working reasonably well at lower cast bullet pressures.

I get the same thing (kinda) using Varget in my 1895 under 400gr Speers. I never see kernels in the barrel, but there are usually a couple that will fall out of the brass. But, since it is the most accurate load I have found for my rifle, I haven't worried about it.

Varget has not left me gasping for breath in any of the applications I have tried. I prefer H4895, for sure. In the 45-70, I like RL-7, IMR3031, and Benchmark. There may be better choices, but those are the ones I have on hand, and they work well.

I have had the same problem in my GG. I switched over to H4895 and have not looked back.

A hunting buddy had lots of unburned powder in his 45.70 Thompson Contender pistol barrel.
Solution was heavier bullets, and slightly faster powder, both raised the chamber pressure enough to burn the powder completely.
VV N133, as I recall.