Fire forming 7.62X39 ?????????

[Clod Stomper]

First, lube generously. I was having the same problem with Winchester cases and a Lee die until I started lubing way beyond what I need to with regular resizing. Second, make sure that your neck expander is set low enough that it doesn't catch the neck while it's being sized down.

Now I don't use my Lee die anymore for necking down. I have a Redding die for that now. But I was able to successfully neck down 7.62x39 with the Lee by using some premium synthetic motor oil. That's probably not necessary, but a good liquid sizing lube is. With the Redding, I have had no problem sizing down with Hornady One Shot.

Will

[Clarinath]

Thanks for the help... Here are the particulars

They are Remington brass with small primers.

My neck sizer is set low enough and wasn't egaging the throat in any way as far as pushing it down.

I crushed 5 in a row, trying all kinds of different things. I lubed them pretty well using Lee Lube 2 for the first 2. I then REALLY lubed them and tried again. Same thing.

One of the cases crushed perfectly so that is even fit in my case go no go gauge.

I tried playing just the tip. Pushing the ram up till it barely sized the neck, then pulling out, relubing and going in again. Even after trying it over and over I still heard that faint "tink" when the case crushed.

I backed off the die to try a neck resize only and it failed.

I have heard Remington brass is kinda soft and maybe that's part of the problem.

[LR1955]

They are Remington brass with small primers. My neck sizer is set low enough and wasn't egaging the throat in any way as far as pushing it down.

I crushed 5 in a row, trying all kinds of different things. I lubed them pretty well using Lee Lube 2 for the first 2. I then REALLY lubed them and tried again. Same thing.

I tried playing just the tip. Pushing the ram up till it barely sized the neck, then pulling out, relubing and going in again. Even after trying it over and over I still heard that faint "tink" when the case crushed.

I backed off the die to try a neck resize only and it failed.

I have heard Remington brass is kinda soft and maybe that's part of the problem.

CL:

You mentioned that you used Lee sizing lube. If you are also using the Lee sizing die, you have found your problems.

First -- get rid of the Lee lube and use a brand that works. I have always recommended spray lube and Dillon but RCBS and a few other companies make pretty much the same thing.

If you are using the Lee sizing die -- get rid of it. The vast majority of sizing problems with the Grendel are caused by the Lee sizing die. Some work real well but we found out on the last Grendel board that if a guy was using the Lee sizing die and was destroying his brass (Grendel or 7.62 X 39) that once he switched to a Redding or Hornady, the problems ceased.

LR55

[warped]

Why bother?

Get some Hornady brass, it nice and cheap, durable and has no volume loss.

Save your 7.62x39 brass for the AK, unless you do not want ammo for that.

[jkingrph]

Why bother?

Get some Hornady brass, it nice and cheap, durable and has no volume loss.

Save your 7.62x39 brass for the AK, unless you do not want ammo for that.

Today that's what I would be doing vs fireforming.

When I bought the 7.62 brass, the Grendel brass was almost unobtainum.

I have purchased and used some of the Hornandy brass and it's very good.

[Clarinath]

I hear ya warped, it was an impulse buy to play with and increase skill set. It isn't something that I would do all the time but the brass was really cheap and I thought I would give it a try. That being said, I have some 7.62 x 39 brass to give away...

LR, it is a Hornady resizer and I haven't had any issues with it, I will have to get some better lube.

Thanks to all for your help.

[txgunner00]

I've done quite a bit of fire-forming using shotgun/ pistol powder and cream of wheat as a filler. It's a bit of a pain to set up then clean my rifle afterward so I usually do a couple hundred at a time. If you are using a gas gun you need to rotate the gas block stop it from cycling and to keep the gunk from being blown into the bolt. The advantage is I don't consume as much powder or bullets and I can do it in my garage. I have a metal bucket w/ lid & 1" hole to contain most of the blast. It needs to be a stout bucket.

Loads-

Powder- Hodgdon Universal clays
Primer- Rem 9 1/2 (I had a lot of these is why I used them, Mag primer would be better)

Winchester brass - 11.5 grains will fully form
IMI brass - takes 14 grains as the brass is much thicker

Process-

FL size with expander ball removed- not necessary to work necks in this step
Prime and charge
Fill with cream of wheat to mid point of neck
plug with a small wad of tissue paper
fire
de-cap and clean brass
FL size w/ expander
load with normal load


*disclaimer* This info is for reference only. Try at your own risk. Works for me. YMMV.

[longdayjake]

if you are giving away 7.62x39 brass I would be happy to take it from you.

[Reno82]

I've done quite a bit of fire-forming using shotgun/ pistol powder and cream of wheat as a filler. It's a bit of a pain to set up then clean my rifle afterward so I usually do a couple hundred at a time. If you are using a gas gun you need to rotate the gas block stop it from cycling and to keep the gunk from being blown into the bolt. The advantage is I don't consume as much powder or bullets and I can do it in my garage. I have a metal bucket w/ lid & 1" hole to contain most of the blast. It needs to be a stout bucket.

Is this cooked or raw? I like the idea.... saves a trip to the range.

[longdayjake]

I don't know how accurate what I am about to say is because I have never used cream of wheat, but I have heard that it doesn't quite create enough pressure to fully form the casing.

[txgunner00]

Is this cooked or raw? I like the idea.... saves a trip to the range.

straight out of the box.

I don't know how accurate what I am about to say is because I have never used cream of wheat, but I have heard that it doesn't quite create enough pressure to fully form the casing.

It will if you get the charge right. Below is a pic of some WIN brass as I was working up the charge.



From the left- unsized 7.62x39, 1st sizing, next 8 have the charge of Universal Clays written on them, next 2 were annealed first and fired with a reduced charge.

two on the right are factory AA 6.5 brass, second from the right is once fired unsized, far right is FL sized.

[longdayjake]

So how does one use cream of wheat? Could you post a description?

[Hoot]

I place a single-ply circle of toilet paper over the powder and top off the case with C.O.W. Then, using a case as a punch, I knock out some circles from a styrofoam cup to make a plug to keep the C.O.W. tidy while chambering the round gently. Make sure you rotate your gas block to keep the stuff out of your gas system. Don't underestimate the power of such a charge. It's still deadly.

Hoot

[Reno82]

So you take the 7.62x39 case and load it. It fits in the 6.5 grendel chamber and you fire it. It then fire forms the neck. Is this right? I've been able to use a press in a 6.5 sizing case to form it without firing it. I've done a 100+ and works great.

[longdayjake]

No. You have to size the 7.62 down to 6.5 first. Then firing it in a 6.5 will force the shoulder and taper to expand and conform to the chamber of your barrel. The result will be a new 6.5 grendel casing.