AIA 7.62x39 cast boolit build

[Alpha1]

Iv never taken a impact cast Ill have to read up on it. The barrel and chamber are hard chromed don't now whether that as any bearing on it.

[dromia]

Shouldn't do, is it completely copper free?

[Alpha1]

As far as I know it is but Ill give it a good scrub just to be on the safe side. Iv started measuring stuff the first thing I did was measure the cartridge overall length this was interesting in that it shows there is quite a jump with the original jacketed bullet. This is good news in that it means I can get away with a longer boolit with out seating the gas check into the case. The jump is about 8mm. As you can see from the pictures the bullet is actually out of the case when used with the Hornady gauge. This could be interesting. A lot will depend on the boolit shape used of course.

[Alpha1]

Ok so the book quotes max cartridge over all length of 2.200. Mine measures 2.540 obviously if you used the standard bullet it would fall out the end of the case at 2.540. This is going to be fun. Im going to have another measure using a popular cast boolit used by lots of reloaders in this calibre and see what the numbers come out at.

[dromia]

That is why you need a an impact slug of the freebore area so that you can get a boolit that will fit the throat rather than groove.

That could explain why the soupcan didn't shoot well especially if it was only sized to above groove, size it to fit the freebore and it should shoot better, don't worry about distance to the lead or trying to reach the rifling with the boolit, if it is sized to the freebore then it will be supported and the jump distance won't matter.

Condom bullet reloading thinking isn't directly applicable to cast.

Just out of interest what is the neck diameter of a fired case?

[Alpha1]

The cast came out different they are .313. The cartridge overall length measured 2.264 so still a little bit of leeway the gas check is in the case neck. So a slightly longer boolit could work but it would depend on the boolit shape. But it gives me some thing to think about.

[Alpha1]

Ill dig out a fired case and measure it and post the results.
This is the boolit Im after but I want it in .314 lots of lube grooves.

This is it next to a popular boolit used by a lot of reloaders in this calibre.

Any way back to reading up measuring and all that kind of stuff.

[dromia]

Size and fit to the freebore, a long unsupported nose sticking into the rifling is not good.

As I said forget the condom bullet thinking, this cast we are talking about. Fit the throat and forget about trying to reach out to the rifling.

It is not the number of lube grooves per se that makes Loverin design so successful but the diameter stepping (tapering) on the driving area they allow so that they fit the freebore.

[Alpha1]

Ok Im curious to find out what the chamber dimensions are now. Ill have a read up on chamber impact thingy. What you said and see if I can give it a go. Hmmm

[dromia]

Remember most of the stuff written about this is from a US perspective, so when they say it is a boolit for the 7.62x39 what they actually mean is this is a boolit for the 7.62x39 to be used in auto and semi auto rifles (mainly AK and SKS). As you are using them in a bolt gun then your boolit needs and priorities will be different.