Old things revisited

[David2011]

Dan,

This is great information. I have heard people talking about very light loads in the 7.62x39 and 8MM Mauser in surplus rifles to the point that they were very quiet. Please, more on developing very light rifle loads. Thanks!

David

[Digital Dan]

David, I have no experience with the 8mm Mauser but would suggest in the most general terms that reduced loads in that cartridge would follow the same path as the .308 Win. If looking for the very lowest sound signature I would consider a pinch of Bullseye and a .310" buckshot. Little bit of grease on the ball wont hurt.

I have vast experience shooting arms chambered for the 7.62x39, such as the AK47, RPD and SKS. My approach was varied. Sometimes I shot them with a minigun, now and then with 2.75" FFARs and if feeling especially grumpy a section or two of TAC fighters. Napalm and cluster bombs were very effective. No lube required.

Sorry, could not resist.....

In truth, I haven't jerked the trigger on any gun chambered for that cartridge.

[castalott]

Dan... A wonderful post! Well written and full of information. More Please! Dale

[Digital Dan]

Should add that my suggestion for the .310 round ball implies that it be paper patched due to the larger bore of the 8mm.

I know, that's cruel and unusual.

[David2011]

Since the pressures are very low I assumed that the process for developing Sneeze level loads would be about the same for all medium sized cases. Is that not correct? I'm thinking of a full cast boolit at minimal velocities. I've loaded powder puff .38 Specials for a few decades and have a 1911 in .45 ACP that functions 100% with 200 grain boolits at 645-650 fps but that represents a lot of work on the gun. The action is glass smooth and goes as far as re-radiusing and polishing the firing pin stop. It took a lot of trial and error with recoil springs, too. Keeping it clean is different from normal loads, too. Since the pressure is too low to seal the brass to the chamber there's a tendency for carbon to build up in the chamber. I've never had that problem in my STI running USPSA Major loads in .40 S&W. The light .45 loads are a ton of fun but it's a more maintenance intensive combination because of the carbon buildup and low recoil impulse. If it gets very dirty the slide doesn't run smoothly either.

[Digital Dan]

David, in general terms I would agree with your assessment. Stray thoughts for whatever they may be worth.

Dunno what platform you're working with for either cartridge, but if you are considering low vel. loads for a Soviet design auto, best of luck.

Thinking that twist rate is important and can pass along that the .300 AAC (twisted 1:8") will work at subsonic velocity with a BHN in the range of 10. I'd not try to use a harder alloy as it would likely lead to gas cutting on the bullet. Use as heavy a bullet as available, it helps boost pressure and gives a cleaner burn and better obturation. This is said not knowing what overall length you'll be loading, you'll have to be the judge of that.

Take a look at shotgun powders, such as Red/Green/Blue Dot. They are bulky, burn clean and seem to work well in both the Sneezer and .44 Mag. 2400 and 4759 will work also, but burns like trash until the pressure starts to move up a bit. I suggest staying away from 800X, it's a bit squirrely for this exercise.

If you don't have a chronograph, get one. It is a most useful tool for evaluating what's happening in the case.

If you have Quick Load it simplifies affairs greatly. It gave direction for the Sneezer and simplified load development a great deal.

[David2011]

Of the rifles I have I would only be interested in light loads in the Yugoslavian Mauser in its original 8mm chambering. I have no interest in tinkering with the SKSs; they're only there to dispense 7.62x39 in a worst case scenario. I've never cast for a rifle and the light loads are intriguing. I've shot a few boxes of Super Colibri .22LR. From a rifle I only hear the firing pin and the bullet impact. I don't expect that level of quiet but if I could shoot accurately at 50 yards with no more report than an air rifle I would consider it a success. Still waiting and hoping for the Hearing Protection Act. Shotgun propellants sound like a good place to start. I only have one .30 caliber rifle, a Garand. I know it will shoot cast but I prefer to shoot jacketed in it. All I would need to try 8mm loads is brass, a mold and a few more hours in the day. The Yugo's bore is very nice and I have dies on hand.

[Digital Dan]

OK then, a few things to consider. Largish case volume and desire to shoot quiet out to 50 yards? No problem (he chuckles softly in the background).

My frame of reference for the Sneezer has been subsonic with a suppressor. This deletes the sonic crack, the other does the muzzle blast report. W/O a suppressor at play your primary source of muzzle blast is the exit pressure, or what is vented from the barrel when the bullet leaves Dodge City. Hundreds of pounds/square inch is quiet, thousands suggest a supersonic gas jet which makes its own crack. I mentioned heavier bullets earlier? Works for me, may not be in your best interest in the short term. In the process of initial review with Quick Load the program opined exit pressures for select loads as low as 600 PSI and as high as several thousands for others. Framed by the powders I had available, the range was from 730 to 3230 psi with the lower numbers represented by shotgun powders as previously referenced. Keep in mind this was calculated with a 180 grain bullet and 19" barrel, your mileage may vary. The highest pressure came from IMR4198 and 2400 was in the mid range.

Given your objectives I'd try the 2400 and likely use some dacron fiber to minimize the issue of position sensitivity. Lacking success, try one of the Dots or equivalent. BHN in the range of 7-8 is sufficient for what you pursue. No crimp, minimum neck tension and if the gun allows for it, seat the bullet to contact the lands...just a kiss.

Best of luck on all!

[OS OK]

An awesome read here Dan...I can't wait to hear about the Yugo and 8mm...not so much in the low pressure but heavies in the 1,800 to 2,000 FPS range if that's in your designs...

thanks . . . charlie