Brass dimples around neck ??

[BackWoods Billy]

Hey guys.I could use a little help again. I have been loading the 7.62x39 for my AK and today when I came home from trying out some new loads I see the brass on the ones I used the 4895 (IMR) had dimples in it. All but about three out of twenty five, the necks where dimpled. I just started fulling around with reloading rifle boolits a month or so ago. I have loaded tons of handgun loads in the past.I started out with 4227 (IMR) 17-18 grans. I shot some of them today and no signs of this. I made some rounds for the first time using the 4895 @ 21-22 grans and I see the dimples. I have been using fed brass CCI LRM second time through brass. These loads didn't seem to be over pressured.I'm sure one of you have come across this before. If you can help me out here it would be great. I forgot to tell you I'm using the Lee 312-155-2R.

Thanks Bill

[littlejack]

Hey to ya Bill:
I believe the dimples in the cases are from either unburnt powder kernals getting between the cartridge case and the chamber wall, or the load of IMR 4895 is too light to cause enough pressure to blow out the case against the chamber walls.
Is there a sooty residue on the outside of the case after firing the round?

[BackWoods Billy]

Hey to ya Bill:
I believe the dimples in the cases are from either unburnt powder kernals getting between the cartridge case and the chamber wall, or the load of IMR 4895 is too light to cause enough pressure to blow out the case against the chamber walls.
Is there a sooty residue on the outside of the case after firing the round?

I didn't notice and there in the tumbler already. Just bought a pound of this powder yesterday.I read on here a few guys using it. It seems that the one @ 22g where the worst..??

[littlejack]

Are the primers in the fired rounds protruding (backed out) some in the cases?

[BackWoods Billy]

Are the primers in the fired rounds protruding (backed out) some in the cases?

The primers look fine. I did notice that the dimples are on only one side of the brass. The dirt on the brass is from the tumbler.

[shotman4]

looks like ejection issue. most autos will ding the brass but a hot load will do more. I dont have load book here but that seems a bit hot for cast. as said I dont have load book. remember the brass is very hot and soft when the case comes out of an auto
A M60 its red

[BackWoods Billy]

looks like ejection issue. most autos will ding the brass but a hot load will do more. I dont have load book here but that seems a bit hot for cast. as said I dont have load book. remember the brass is very hot and soft when the case comes out of an auto
A M60 its red

Now that I noticed that there on one side of the brass I think you my be right. This is where I got my data for that load. He is using a 180 grain boolit so I thought I'd be safe with that load. Here's the link..
http://castboolits.gunloads.com/show...-7-62X39/page4

[NSP64]

Billy, How many times have the brass been reloaded since you annealed the necks?
Also, the magnum primer may be pushing the boolit and powder out before complete ignition occurs. Are you crimping the boolits in the case?
the dimples are caused by unburnt powder kernals being on the outside of the case before it expands to fit the chamber .
What works good with a 180 gr boolit, might not work with a 155gr boolit, it may need the extra weight and resistance to get complete ignition.
you can try regular LR Primer or maybe LP Primer.

[historicfirearms]

It looks like ejection dings to me too. All my AKs have done this. I don't think it's a big deal, just run them through your sizer and most of the dings will be ironed out. If the dings are really bad you might want to scrap the brass or save it for light loadings.

[JonB_in_Glencoe]

Bill,
I'm about to give you a mild lecture.

Don't use load data from a link from the internet, even if it was from Junior, but you did NOT even use the same boolit !!! It's best to use data from a known published source

If you don't have one, you should get a copy of the Lyman cast bullet handbook rev #4. While I've never loaded 7.62x39, I took a quick look in that manual. They don't list 4895 for any 7.62x39 boolit loads, now that alone doesn't mean too much, but then I looked at a similar, but more powerful cartridge, the 7.62nato (308 win), the only loads where they use 4895 is with a 180 gr. boolit. So by reasoning of deduction, I conclude that 4895 isn't the best powder for a lighter boolit in a less powerful cartridge. It is probably a slower burning powder.
How was your accuracy ?

OK, the Lecture is over.

With all that said, I am pretty sure your AK dinged that brass, because of HARD ejection from a hot load, especially if the Dings are uniform.

I'd try a faster powder with that boolit, like AA 5744.
Good Luck,
Jon

[NSP64]

Bill, Hodgdon website shows a Hornady 150 gr bullet over starting charge of 27.0 gr of 4895. Max is 28.0 .
Try increasing powder to min starting load and switching to a large rifle primer(not magnum). You can always drop the charge down until it won't work the action.

[NSP64]

OK, I dug up my notes from when I owned an SKS. I was using lee 155gr boolits over IMR 4895 and fed LR primers getting best accuracy at 22.2 gr and operating as a semi auto.

[saint_iverson]

Hodgdon web site??? NSP if it is from Hodgdon the powder MAY be H4895, not to be confused with IMR 4895. They are different powders and loadouts cannot be interchanged, if my memory serves me correctly, the difference between the 2 is at least by a factor of 10% base line depending on the caliber.

[saint_iverson]

I don't want to be too presumptuous here, but I have 3 load books at my fingertips, one from Hodgdon, one Lyman, one Lee-NONE have any loadouts for the 7.62x39 using IMR 4895, as well as the IMR/Win/Hod website listed no loads using the IMR4895. This powder seems to be not suitable for use in the 7.62x39 caliber.

[JonB_in_Glencoe]

Bill, Hodgdon website shows a Hornady 150 gr bullet over starting charge of 27.0 gr of 4895. Max is 28.0 .
Try increasing powder to min starting load and switching to a large rifle primer(not magnum). You can always drop the charge down until it won't work the action.

NSP,
Is this Hodgdon website data for cast boolits ? or jacketed ?
Jon

[flounderman]

one thing, you can't have it both ways. You tell him it's because the load is too hot and in the same paragraph you tell him the powder is too slow for that cartridge. He's not getting enough pressure quick enough to seal the case from blow by. needs a heavier bullet or faster powder. also possible bullet is not leaving the barrel fast enough allowing more time for gas to bleed into the piston and that the bolt is unlocking prematurely. necks may be sized considerably smaller than chamber neck area. make sure the neck isn't being sized or expanded for 308 instead of the larger 7.62 x 39

[303Guy]

It's unlikely to be from premature bolt unlocking. My bolt action 25-303 does it with fairly warm loads with H4350/AR2209. Not often - just every once in a while. Those are 85gr bullets. It hasn't done it with any other bullet. There was no debris in the dent on extraction. This was a neck sized only case.

[BackWoods Billy]

Ok..Thanks for all the help here you guys..I now have many thing to look at..I have tried to look up load data for this boolit and there just is none out there. Like I said above,I started out using the 4895 (IMR) @ 17g. It worked ok with maybe a very small ding on the side of the brass. I tried the 2400 and it really didn't work the action. Every thing I am reading on here is the slower powders are working best. I'm sizing my necks to .311 and my boolits are sized to .313. I put a pretty good crimp on them. I lapped out my mold to get the .313 and the boolit is round.Made the Lee sizer .313 too. So I'm pretty sure I have a good tight fit there. Out of all my loads so fare,the 22g of 4895 gave me the best grouping but not that great.(3.75 @ 50yds) But what do you want from a AK. The thing here is I'm having fun trying to make this thing shot..Maybe I will just have to settle for that with this gun. Thanks again for all the feed back.
Bill.

[tomme boy]

Too slow a powder and too light a charge. The brass is collapsing. Happens more with jacketed than cast. I will see if I can find more pics somewhere of it.

Go to a faster powder and it will go away.

[tomme boy]

Attachment 57027That is NOT a dent... that is case collapse. It is a phenomenon caused by a low pressure load that does not seal the neck and thus gas escapes around to the case and the pressure is trapped between the case and the chamber. Notice the soot on the neck/shoulder area, that is a sign of either not enough powder, or too slow of powder. It's a situation that has more to do with the pressure curve. The peak pressure is occurring too late for the neck to seal. There are several factors that contribute to the pressure curve, ignition from the primer, burn rate of the powder, and the length of the barrel.

The above is what I found.