Seating depth

[Alpha1]

Why 7.62x39. Using cast boolits. I shoot a 150 grain .311 boolit in my 7.62x39 I am toying with a 180grain .314 mould a the moment. I have discovered my 7.62x39 prefers longer bore riding boolits with lots of lube groves rather than the short tin can type. The difference down range is quite surprising. (I only use these loads at short range.)
I am tempted to go large on jacketed. At the moment I am using 125 grain jacketed bullets but I have some 170grain I am looking to try just as soon as I can fathom out how to use quick load. The only thing to remember with the 7.62x39 is that the bullet is .311/.312 not .308.
Or may be I can get some one to run the numbers for me in quick load.

[meles meles]

Why x39 ? It's a small case, but big enough to seat a large bullet. If we're remaining subsonic we don't need a lot of powder so it seems a good combination. If there are other suggestions, maybe a 45-70 necked out to .5 we'd be delighted to consider them.

[Alpha1]

I like the 7.62x39 caliber I think I can get it to work with a heavier bullet just trying to get my head around quick load then I will give it a go.

[Laurie]

Lapua makes a 0.310" 200gn version of its D46 rebated BT projectile specifically for subsonic 7.62X39mm ammunition. The factory subsonic round is claimed to feed and cycle the action reliably in an umodified AK47 and its derivatives. Don't ask me how they get the 200 into that little case within the standard COAL!

Then, have a look at

http://members.shaw.ca/cronhelm/762Page.html

It lists 7gn Viht N310 under a 200gn jacketed bullet, but note the section on the essential enlarging the flash-hole, use of a magnum primer and a lubed bullet.

Another powder listed for 200gn cast lead bullets in the cartridge uses IMR Trail Boss, a bulky 'fluffy' powder that is widely used with both jacketed and cast lead bullets in subsonic rifle loads. I'd have thought that would make a good starting point for such a project.

Note the link to the article on special techniques for handloading subsonics:

http://members.shaw.ca/cronhelm/DevelopSubsonic.html

Producing a reliable and safe subsonic load for a rifle cartridge whose designer intended it to be supersonic is not always simple, and may not be a great idea for a new handloader like yourself.

There is a further link to articles by P.T. Kekonnen, a guy who has put a lot of interesting stuff on the Web

http://guns.connect.fi/gow/arcane1.html

[Alpha1]

I have done quite a bit of reloading for this cartridge the business of enlarging the flash holes well hmm. I tried the same load with both enlarged and standard cases and did not notice any difference.
Lots of interesting info though thanks for that.

[Laurie]

I don't think you'd expect to notice any performance difference, not with charge weights under 10gn. The issue as I understand it is one of reliability / safety with small charges of pistol powders. It's a standard technique developed back in the days when use of ultra light loads was much more common than now but for economy, not for moderated rifles. Whether it's a 'must' for the small capacity 7.62X39 compared to say the .30-06 that these guys would mostly have used, I wouldn't know. Likewise, whether the use of a truly modern powder developed for ultra-mild revolver loads, ie Trail Boss, affects ignition reliability positively, again I wouldn't know.

The problem with weird ignition and charge burn effects caused by going outside the box is that there is no guarantee of anything happening or not happening. A load may be 100% safe for 99 users forever, and the 100th unlucky guy has a secondary pressure / detonation effect with his first try that breaks the gun and injures him. Everybody then says, "The silly clod must have used a double-charge!"

What I do know that when C.E. Harris advises something, it's worth noting. Harris must have fired hundreds of thousands of test loads and knew more about handloading, especially with reduced velocity lead bullet rifle loads than almost any man of his period.

[dromia]

Harris is indeed the reference for this type of loading with cast. I have shot 10s if not 100s of thousands of cast boolit rounds in a wide variety of calibres over the years with never a problem with fast pistol powders using Harris's recommendations. I never use jacketed bullets for reduced loading. From my understanding of SEE (Brownell's work) it seems an issue of reduced loads with rifle powders.

Why not use a cartridge like the 300 Whisper or Blackout anyway they were designed for the application you desire and have data.

[phaedra1106]

As Dromia says the 300 aac or Whisper is ideal for sub-sonic loads. I use 3.1gr of N310 with a non-gas checked soupcan cast boolit but have also used 210gr spire point cast with good results but as I do 99% of my shooting at 25m the soupcan uses less powder and does the job very nicely indeed. And with the reduced loads there is very, very little case expansion so re-sizing is very easy (no lube needed) and working of the brass is kept to a minimum.

The 300aac also shoots nicely at longer rangers at around 1980fps using 16.5gr of H110 and 168gr jacketed bullets.

[meles meles]

Good suggestions, oomans, good suggestions. Thinking a little more, we're pondering something like a Ruger falling block or CZ in .458 and some big lead ingots travelling at about 1,000 fps. Should be able to knock the engine block out of Farmer Giles' Massey Ferguson with those...