Home Forums Lever Action Central Big Bore Levers Subsonic Loads for the 45-70?

I have a Marlin stainless guide gun with the barrel shortened to 16 inches and threaded. I plan to put my sons and grandson in the good spots this season while I do some covert meat hunting. I am still developing a 405 grain load using H4895. Hodgdon has determined that H4895 lends itself to reduced loads. The company recommends starting at 60% of the maximum published charge for a given cartridge/bullet combination and working up from there.

I loaded five sets of cartridges with charges progressing one grain per set yesterday. My quest is to find the largest charge that will be "whisper quiet" using my Silencerco Hybrid Suppressor.

Now, if I can just find some time and dry weather to try them out!

Do any of you have experience developing and shooting subsonic 45-70 rounds through a suppressor.

T.S.

Me having suppressor experience, and loving the 45/70 here are my thoughts. Whatever powder you use, don't go below 30% case fill. Use a stout crimp to encourage complete powder burning. I have some data if you need it, don't use cast bullets with a suppressor, a lot of centerfire suppressors aren't user serviceable or cleanable. At your target range, say 50 yards, put your cellphone in the area of the target, and record a video of the shot, see if the sounds are acceptable to you.

Here is 308, Sierra 180gr roundnose that I moly coated. About 950 fps at 50 yards.

.308 Subsonic

Thanks for the advice Jeff. Yes, the 30% of case capacity caution is why I am not using hot pistol powders like some. The smallest charge I have loaded for testing is 30 grains. I'm pretty sure I will be able to go higher than that and still maintain subsonic velocities.

I have a 30-30 load using a 220 grain jacketed Hornady FPs that is that is whisper quiet. By whisper quiet, I mean the muzzle report is a "poof" and the bullet impact is a loud "thwack".Also, I purchased some Atomic brand subsonics for my suppressed 308 (175 grain Sierra Matchking) and they are whisper quiet as well. I'm hoping for the same with these 405 grain jacketed flat nose bullets.

Have you been able to find a 45-70 load that is "whisper quiet" when suppressed?

T.S.

12.0 gr Unique and a 405gr cast RNFP gives 1050 fps in my 18.5" Marlin.

Good info here:

http://www.gmdr.com/lever/lowveldata.htm

Thanks Montana. - T.S.

That's going to be hard to beat. My records show 10 grs of Unique, or 11 grs of Herco, with the 405 jacketed, no filler. This was a Marlin Guide gun. Make sure the bullet is going out the barrel, every time as you test them this low. I home moly my suppressor bullets to lube them.

LOL!!!! So far, the loud smack of the bullet tells me it got out. :-) I also need to make sure the bullet is stabilized and printing round holes with the given load before screwing on my suppressor.

Jeff, what is the advantage of lubing the bullet? Are you moly coating lead?

T.S.

If it were me I'd look to use something like a RCBS 45-500 FN without a GC and get that bullet coated if using a suppressor. Cast bullets have a lot less friction compared to jacketed bullets.

At 1000 fps it is not going to be loud, though a longer barrel would help if not using a suppressor. That particular bullet is designed to fit and function in the Marlin but importantly it takes up a lot of internal space, making reliable sub sonic loads easier to achieve.

Roger that JFE. - T.S.

Just don't brush off a bullet/round you can't account for without checking the bore. No, I am moly coating jacketed. Back in the Stone age ...'70's. We found that the true "cat sneeze" bullet should be lubed to BE SURE it cleared the barrel, we used Crisco. To moly coat, I'm using a small rock tumbler, molybdenum disulfide, and airgun BB's, tumbling them for two hours or so gives lube for the bullet and bore; the accuracy with lubed bullets show improvement also.

This +1; you'll have a much easier and safer time working out a good load with a cast bullet, especially if it's of appropriate hardness and not the excessively hard commercial alloys that are so common.

Also, this is very important - when developing subsonic reduced loads, work DOWN in powder charge, not up! You aren't worried about an upper pressure limit, you're trying to stay above the lower limit of sticking a bullet in the bore, so you work down towards that instead of guessing at a low charge when you don't know where the sticking point is. That happens at much higher velocity for jacketed bullets than for cast. As velocity decreases, you'll notice velocity variation of the jacketed bullets will go nuts shortly before you stick bullets. Cast bullets should be fine down to 600 fps or less, but your jacketed bullet may stick as high as 800-900 fps in that big 45/70 case.

It might be overly optimistic to expect "whisper quiet" from a 16" 45/70; that's a lot harder to do in the big bore than in medium/small bores. 30+ grain powder charges won't help you in that goal either; that's why most experienced suppressed/subsonic handloaders look to small charges of fast pistol powders.

Russel I did something similar last year and cut my 1895GS to 16" for use with a Hybrid. H4895 will work but running the numbers on Quickload, the max charge of H4895 will result in only 66% of the powder being burned in the barrel. The rest has to go somewhere and what doesn't get shot out will wind up in your action and suppressor. I have found Unique and Trail Boss are much better suited for subsonic loads and result in 100% burn for that length barrel. Of the two, I get quieter loads using TB.

If you can find them the Remington 405 JSPs work really well though lead bullets work fine if you powder coat them first. This prevents sticky waxy lubes from building up inside your can since the Hybrid cannot be taken apart for cleaning. I have had good luck with the Lee 405 bullet for subsonic 45-70 and 458 Socom. If you want to shoot me a PM I can share whatever subsonic load data I have for the 45-70. FWIW I just finished my 44 SBR build so am getting ready to convert another 1895GS to a 12" SBR which should make for easier handling with a can in place. Even at 16" I find the gun somewhat unwieldy and nose heavy with a can.

12 grains of Trail Boss with a 405 homecast tumble lubed. Velocity 980 fps. Good accuracy. Not shot through a can.

Thanks guys.

I have a hollow base mold for the 45 muzzleloader. Wondered about it in the 45-70? Maybe at the low velocity for a suppressed marlin turn it around, cavity forward, powdercoat and use TB for the load. 100 yards or less I'm guessing. May or may not stabilize. I have had too may projects to get to this one.

That bullet is a tumble lube wadcutter style of bullet. Was thinking of dead soft lead to cast them.

rusty, I don't have enough experience with this to answer your question or even express an opinion. Sorry. - T.S.

Sounds like a good experiment. Cast some up and see what shakes out. But I don't have approval on my Hybrid can yet. ATF is slow to slower at times. Would get me moving to know I was picking up the Silencerco. And of course the threading isn't done yet. Will require some smithing. Have the desire to set up the Marlin as a threaded takedown. Then the loads can be experimented with. Rusty.

I tried some loads of 405 Remington FNSP using large rifle CCI primers over 15.2 grains of Unique yesterday. I had several Failures to Fire even though the primers were clearly struck hard. Plus, among those that fired I had sticky extraction. The primers were not flattened and the brass looked OK but I think I was experiencing high pressure spikes. I put those loads away and will disassemble them this week. I am going to stick with my H4895 loads. They shoot dirty like Remington's trapdoor loads but are well-mannered and appear accurate.

T.S.

AA5744 lends itself to light loadsçl as well. 15 to 20 grains works nicely in my Buffalo Classic.