Fire forming 6mm AI

[Atomic_Cowboy]

Hello all,

I am currently building a rifle in 6mm Ackley Improved.

Only Remington and Winchester offer unfired brass. However, I am considering buying Hornady or Federal ammo off the shelf to perhaps get a better alloy.

So the question is: Is there one brass better for fire forming over any other?

Thanks in advance.
DG

 

[Preacher]

I always preferred Federal ammo if I was going to shoot factory to fireform......

 

[Cheechako]

DG

You didn't say, but what exactly do you find unacceptable with either Rem or Win brass? I shoot WW and a friend shoots Rem and we have not had any complaints after sorting the bulk stuff.

If you want to spend the money you can use 7mm Mauser brass that is available in other brands.

One suggestion - decide on the brass first and then have your reamer ground and barrel chambered to match it.

Ray

 

[Atomic_Cowboy]

Ray

I personally don't have a problem with either. However, I have read: "Remington brass has problems splitting when fire formed." and on other forums people like the .243 AI because of brass selection but still choose the 6mm AI.

So, I guess the long and the short of it is: I am curious if Hornady or Federal makes a better brass,longer lifetime), better also meaning better than Winchester or Remington. Some sources claim Hornady and Federal may both use Rem brass with respective head stamps. Maybe I should buy a box of each and see which lasts the longest? IDK?

Also, what is the preferred method for fire forming? If I am going to buy and load virgin brass and shoot bullets, I just as well buy factory ammo, after considering time. But the cream of wheat method is likely cheaper and saves barrel life, but does it do the job?

Thanks again,
DG

Knowing you can read whatever answer you like on the internet is half the battle.

 

[number40Fan]

Shooting the fireforming loads is half the fun. Some people have stated that the forming loads shot better than what they could do with the formed loads. For my .243 AI I bought 100 Winchester cases. Did all of the case prep and then annealed the shoulder/neck area. Loaded them up and even though I have only fired 41 rounds through it, they have all come out nice and sharp. The first round fired was a 4 time,maybe 5...can't remember right now) loaded case. I annealed it and it came out perfect too.

The only reason I am going with the annealing route is because of what I have read with the split neck and shoulders that others have been having. Some of them people have been using expensive brass too.

 

[AckleymanII]

I have never annealed any 243 AI or 6mm AI load. Also, I have never had any necks split in either cases. I used Rem brass in my 243AI and Win Brass in the 6mm Rem AI.

In one 26" 6mm AI Douglas Stainless barerl, I used a load of 48.5g of Win 760 to fire form my Winchester cases in one barrel shooting Fed 210's and 70g Nosler Ballistic tips getting groups in the .400 or a little less range at 3850 fps.

In another Shelin 26" barrel in 6mm AI, the fire forming load was 50.5g of Win 760 shooting 3/8" groups at 4050 fps. The formed load in this barrel was 51.5g with the 70's going 4150 fps with no pressure.

I use Winchester on the 6mm AI.

Good luck!

 

[Cheechako]

DG

I have never had any split necks while forming hundreds of cases for my 244 and 280 Ackleys.

Believe it or don't, but sometimes cases will split if you are using too light of a fore-forming load. The load should be one at the top-end of the loads for the original case.

JMHO

Ray

 

[Ackman]

Fireforming with a filler is unnecessary. Use bullets. Start within about 1gr. of top end for the 6mm and work up til you find best accuracy. It'll be going quite a bit faster than a regular 6mm. Look at Keith's fireform loads....they're way beyond what's in the reloading manual as top end for a standard 6mm and also considerably faster.

Annealing new brass isn't necessary either, it's already annealed. Domestic manufacturers just polish cases so it won't show. Fireforming many thousands of cases to Ackley Improved, I've never once had a split neck or shoulder. Brass will split during fireforming if the chamber's too long. You want enough crush on the case,contact point is only at the neck/shoulder junction) to definitely feel it when the bolt closes.

 

[RJinTexas]

I have limited experience fireforming but I've got to agree with Ackman. Last month we fireformed 300 rounds that I loaded for a friend's new 6mmAI 16LB varmint rifle. New 6mm Rem brass was used, all the necks fully formed, not one split, we did pierce one primer,AND IT WAS VERY FLAT). It was close to 100 degrees my buddy hadn't cleaned his rifle in over 100rds.,common practice when shooting PD'S after barrel is broke in) None of the other cases showed pressure signs and case expansion wasn't excessive. You must pay close attention to your headspacing as Ackman stated. I also make certain the bullets are touching the rifling.

I measured several new RP & WW cases, here's what I found, RP's neck walls were thicker they avg 0.0135 to 0.014 while WW's were all very close to 0.013 and the necks on the RP's were a little more dinged up and about half had a slight lip at the top. If your buying the reamer as someone else suggested I'd seat the longest bullet you plan to use in the brass of your choice and mail it to PT&G to have a reamer made.

NOTE: This load was not run over my chronograph, I'm sure some of the speed shown by QL will be lost to pressure being used to form the case. Range testing of 5-3 shot groups averaged 0.425 and it more then did a number on PD's out passed 600yds.

Quick Load Data
87gr Vmax - 40.5gr/Varget - CCI200 - RP's nk sized & trimmed @ 2.230 - aol @ 2.940 to fit this chamber - 54444psi = 3359fps

RJ

 

[Atomic_Cowboy]

Thanks everyone for your inputs!!!

-DG