my adventures in converting and using x39 brass

[mel]

so since i have a much much larger stockpile of lrp vs srp's and u can still get ur hands on more lrp's i decided to try my hand at using some converted 7.62x39 brass.
so far the process has been very simple.
ordered up a cheap once fired batch of mixed headstamp brass ( the majority of it is geco and ppu with some s@b mixxed in


alls i had to do was lube the cases and run them threw my fl grendel die , i had to run my die in slightly more then i would resizing normal gren brass
grendel case on the right

grendel case on bottom

and a bunch of them formed



i did make one mistake right off the bat , i took the first 10 cases i tried an anealed them before forming , this doesnt work makes the case to soft and it crushes it when trying to form it , what im doing now is forming them then ill fire form it and then ill aneal them

next step which is comming is fire forming them , which is a perfect use for those slightly oversized mid south mm 123g match bullets i have , after that ill start working up loads with this brass with alliant ppv and nosler 90g varmagedeons , and then ar comp and nosler 123g cc hpbt , and thats all i plan on loading in this brass

[tdbru]

Mel,
if you have a way to, measure the neck thickness of one of your grendel cases, and then these sized down russian short cases. if the necks have thickened up a bit i'd recommend neck turning so that the bullet will be able to release from the case in the chamber. otherwise you'll get more pressure, maybe over max.
-tdbru

[mel]

Mel,
if you have a way to, measure the neck thickness of one of your grendel cases, and then these sized down russian short cases. if the necks have thickened up a bit i'd recommend neck turning so that the bullet will be able to release from the case in the chamber. otherwise you'll get more pressure, maybe over max.
-tdbru

i will i just didnt have time today to measure them

[Lemonaid]

I recommend making a few dummy rounds and see if they will cycle before loading any, it can save a lot of angst.

[StoneHendge]

Gotta love the USPS. Turns out Diamond K is 12 miles from me and I haven't gotten mine yet! Did you end up with any small rifle or berdan primed brass?

[mel]

Gotta love the USPS. Turns out Diamond K is 12 miles from me and I haven't gotten mine yet! Did you end up with any small rifle or berdan primed brass?

been threw half of them so far and no sr or berdan

[SCJim]

interesting experiment. As lemonaid suggested make a few dummy rounds and check for cycling. Check the neck diameter after seating a bullet to make sure the will have at least .002 to .003 room for the neck to expand on firing. That extra brass went somewhere, you may get or have a doughnut on the inside of the shoulder neck junction

[JSH]

I would anneal before you fire form them. It will give you a better case, no rounded shoulders.

[mel]

I would anneal before you fire form them. It will give you a better case, no rounded shoulders.

the 4 on the left side of theblock are anealed , was going to fire form those and a few that werent anealed yet to see if theres any difference before i fireform them all .
ive seen ppl say to do it both ways so i figured id try both and see what seems to work better

[mel]

.001 thou diff in neck thickness and .003 thou larger neck od on the x39 brass

[LR1955]

Mel:

You will get donuts with about a third of your brass when you fireform. They will get worse for the next two or three shots you will get before the primer pockets open up on the 7.62X39 brass and you throw it away.

I ran a internal reamer through the brass after fireforming and that seemed to be OK for the rest of the life of the 7.62 X 39 brass which was another two or three shots.

I never had an incident of 7.62 X 39 brass not chambering and extracting easily but I think part of the reason why the life was so short was because even though the round would chamber, there was not enough space left for the neck to expand without some high pressure. Also I am betting 7.62 X 39 brass uses a different alloy than Grendel brass and is softer. No evidence to show but just speculation.

LR55

[SCJim]

.001 thou diff in neck thickness and .003 thou larger neck od on the x39 brass

Measure a fired case and one of your wildcats with a bullet seated to make sure you have at least .003 neck clearance for expansion to prevent pressure spikes

[mel]

Measure a fired case and one of your wildcats with a bullet seated to make sure you have at least .003 neck clearance for expansion to prevent pressure spikes

ima do that here shortly , so ima fire form with some 123g pills my normal load in hornaday brass and std sr primers is 27.7g , what yall think about for a starting poin in the x39 stuff 24.5g?

[mel]

Od of x39 loaded is .292 od of fired grendel is .298

[tdbru]

Mel,
my reformed 7.62x39 to 6.5 Grendel cases show pressure (not good) at 2 grains below what i normally load in hornady small rifle primer 6.5 Grendel cases. so i think your 3gr. below normal is prudent. i think there's a difference in amount of primer material between even small rifle magnum and standard large rifle. it's a pain to turn case necks, but in this case i'd recommend it (pun intended). depending upon brass manufacturer, i've not run into loosening primer pockets with winchester, federal, or remington reformed. other brands i don't have enough reloads on them to tell. once real grendel cases / ammo became available, that's what i have used since.
-tdbru