Fireforming Need Advice

[SHRTSHTR]

To fireform with pistol powder, cornmeal and tissue or bullet, that is the question.

I just received my custom 338 Lapua Improved. I plan on breaking in the barrel 1st using live round. Once this is completed I am not sure which way I want to go. I have 200 pcs. Lapua brass. I will probably stick with the 1st 100 cases for now.

I hate to shoot 300 smk's for the 1st 100 rounds because I do not think that I am really accomplishing anything other than fireforming. I will try and explain. I don't think I can shoot full charges that the 338 LAI will require out of a standard Lapua case before it is fireformed. I was using 90.0 H1000 in my standard 338 Lapua. I need to test this 1st but I should be somewhere between 100-102 grains H1000.

I do plan on working up a load 1st thing. Neck sizing only to first see where my max load is using 20 or so cases to do barrel breakin and load development. I will reuse these 20 cases during this process. Besides, I need some fired cases for my Neil Jones dies.

I hear it takes 2-3 firings to fully form a Ackley Improved cartridge. I think you see where I am going here, even if I don't Seems like a lot of wasted barrel life to me. I am sure there is a better way of doing this without wasting barrel life and getting my load data in the least amount of shots as possible. Thanks for reading.

Ray

 

[TOM H]

Ray, I fireform alot using COW method for my Ackley rifles latest 280AI. I used 18gr Bulleye and that got my case formed 99% and I used 14gr for the 243AI.


What I do is load up some test cases starting at 20gr Bulleye go up 1gr to 30grs you should form fine within that range I'm guessing. The shoulders may be alitttle rounded not those sharp shoulders but you can get that with a bullet load. Well good luck

 

[kdog70]

I do not know about the big bores (338) or its barrel life, but for my 260 and 243's AI I just shoot a full house regular load and get real good accuracy out of it. In three AI chambers, I shoot normal loads to fire form, it gives me practice behind the gun and at least for me its been decently accurate and not too bad off the chrono tape as far as speed, Es.

When I say decent accuracy I mean I shoot maybe 3/4 ish MOA some better some worse fire forming then once they are formed I can get it down to .5 MOA ish. Either way everyone their own way I suppose. Good luck and have fun with the cannon.

 

[J E Custom]

I have found that well prepaired loads can be fired with excellent accuracy while they are being
fire Formed so I load the round with a good hunting bullet and a medimum powder charge (1 or
2 grains off the max and do the break in , get a good zero and hunt with the rest.

This way there is no wasted effort and you can use the rifle and ammo while fire forming.

The last rifle that I fire formed this way was a 223 AI and the accuracy was excellent. (Average
group size was .221 and the best group @ 100 yards was .110). That is less than 1/4 MOA
and I am hunting with the rest while fire forming all of my brass.

The increase in velocity with the fire formed brass will normally net you 100 to 200 ft/sec more
but I like using the brass for hunting while it is fire formed.

After fire forming I can work up heavy loads with big expensive bullets, but still enjoy the rifle
while doing so.

This is just the way I fire form and with this method the brass is fully formed and ready to
load with the bullets and velocities you wanted.

I have tried the COW method and it is very boring and doesn't do as good of a job as a good
pressure load + it requires time, powder,primers and consumables that can't be used for any thing else.

No offense to the guys that do there fire forming this way I just like to use the rifle while I fire form.

J E CUSTOM

 

[Boss Hoss]

Just to let you know I have three 338 Lapua Imp (338 Slowpokes) and all were formed by filling 3/4 with Bulleseye and a little cotton to keep it in -- then firing.

Have done many others this way as well. Works like a charm.

 

[SHRTSHTR]

Wow, lots of ways to shin a Kitty . I would like to be able to load close to desired load with Virgin Lapua brass once I establish where that is.

It also seems that just fireforming with pistol powder and tissue would get the job done as well. How much do you pack down the tissue. I'm thinking a little ram rod...like a Muzzle loader. Sounds like a very boring procedure that would likely only need to be done once....concidering I have 200 cases. Should have done this on the 4th of July in my rocking chair.

Boss,
Could you tell me how many grains 3/4 full is . i would feel a little better about something I can measure. I'm sure I do not need to measure to the grain .

Good info guys, will let you know which way I decide to go.

 

[Boss Hoss]

Wow, lots of ways to shin a Kitty . I would like to be able to load close to desired load with Virgin Lapua brass once I establish where that is.

It also seems that just fireforming with pistol powder and tissue would get the job done as well. How much do you pack down the tissue. I'm thinking a little ram rod...like a Muzzle loader. Sounds like a very boring procedure that would likely only need to be done once....concidering I have 200 cases. Should have done this on the 4th of July in my rocking chair.

Boss,
Could you tell me how many grains 3/4 full is . i would feel a little better about something I can measure. I'm sure I do not need to measure to the grain .

Good info guys, will let you know which way I decide to go.

Have never weighed them even with the 6mm PPC cases always 70 to 75% on the powder measure a tiny bit of a cotton ball pushed into the top with a old dental pick. Speedy Gonzalez taught me this trick---this is the way he forms his brass.

 

[Freebore]

Have never weighed them even with the 6mm PPC cases always 70 to 75% on the powder measure a tiny bit of a cotton ball pushed into the top with a old dental pick. Speedy Gonzalez taught me this trick---this is the way he forms his brass.

I've have always used the COW method, for a 243AI 18gr powder, COW 1/2 way up neck and the eraser side of a pencil with some doubled over TP, I prefer Charmin, cut a perfect size patch. This method makes a bit of mess in the barrel.

This way sounds alot cleaner, I'm just not sure about the building of pressure without the COW but with a case 70-75% full of fast pistol powder (actually shotgun powder) it may just be the ticket. I'll have to try this next time I wear out my Lapua brass..like that's ever happened.

Word of caution about barrel heat as it will heat up blasting that fast powder out the barrel. So pay attention to that too. It takes some time. The 4th probably would have been a good time to do just that.

 

[SHRTSHTR]

Alright guys, I've got the picture now. I like the cotton ball idea and is probably cheaper that Charmin!

 

[Buffalobob]

If I was you I would give Boss's method an honest try. If it does what he says then you are ahead of the game.

I have used the COW on Lapua 338 brass and it does not give you a sharp shoulder. You still have to fire one bullet to actually get to final dimensions. However that one bullet has killed several animals for me and several for SS7MM being as we both shoot 7AMs and used the COW method.

Second point is that COW is messy and the stuff cakes up in your barrel and in your chamber and you have to clean the chamber every four or five rounds.

Here are a few videos of how to do it with cornmeal. Notice the cleaning rod is right there handy.


YouTube - Microcystis's Channel

YouTube - Microcystis's Channel


YouTube - Microcystis's Channel

 

[chris matthews]

Anther method would be give Lonnie Hummel at Hornady a call and get a hydraulic forming die for it...then you'll have fully formed cases without anything down your barrel.

 

[Boss Hoss]

A good point above that I did not cover---HEAT! The way I keep the tube cool is with compressed air can turned upside down to come out as a liquid. A compressor with an air hose will also work it just takes a little longer when you are doing a couple of hundred rounds.

 

[BountyHunter]

You can get a lot of practice using standard fireforming loads. I use that with my 338 AI.

They will final form with one firing. 60,000 PSI moves the brass.

The Hornday hydralic dies work well and Lonnie Hummel is the man for that.

If using the COW take the brake off. Saw the brake blow off a gun with debris building up in one while using the COW. Watch the heat build up also.

BH

 

[SHRTSHTR]

Thanks for all the input guys. I hope to be at the range in a couple of days.

Ray