New to fireforming; some questions

[Deleted old_dood]

I've got a 223AI chambered barrel on the way for my Savage. Can I just fireform with a known good load that I've been using (60g FB over 24.8g IMR4895)? Since it's a new barrel, would I be better off shooting lighter bullets? I do have new Lapua brass. How many firings would it take before the cases are fully formed?

thanks

 

[Catfish]

I have done a lot of fire forming with while hunting. If you find a good accurate load with a high pressure load that is the best and cheapest way to fire form because you never have to fire form on the range only. If you try to fire form with to lite of a load you will get un formed cases and have to fire again to form.

 

[Tommie]

Your known load should fully form the cases just fine.

 

[Deleted old_dood]

Ah, good. fortunately I ordered my dies last weekend because Pac Nor has just shipped the barrel. They originally told me 10 weeks but it only took 6. I've got those 60's for fireforming but now have a box of 500 77g TMK plus plenty of Varget and RL15. Also got the 223AI GO gauge from Manson.

 

[SmokinJoe]

So, it looks like you are planning to set headspace with the go-gage, which is ideally the way to do an AI. However, before you start fireforming, check that there is a good crush fit when you close the bolt on a round. If you don't have the crush fit, tighten up the headspace a little until you do. That crush fit is what holds the brass securely in place as the brass expands during fireforming and prevents longitudinal brass stretch which would result in premature brass failure (head seperations). I think you will like the AI once you learn how to deal with it.

 

[Deleted old_dood]

So, it looks like you are planning to set headspace with the go-gage, which is ideally the way to do an AI. However, before you start fireforming, check that there is a good crush fit when you close the bolt on a round. If you don't have the crush fit, tighten up the headspace a little until you do. That crush fit is what holds the brass securely in place as the brass expands during fireforming and prevents longitudinal brass stretch which would result in premature brass failure (head seperations). I think you will like the AI once you learn how to deal with it.

is that a crush fit with unformed brass? I posted here several weeks back about headspacing the new barrel. consensus was use a 223AI GO guage for the GO and a conventional 223 GO for the NOGO. Will that generally result in a crush fit on un formed brass?

 

[John from MN]

Yes, you want a light crush fit with unformed cases.

 

[Jason Boersma]

Use your load but seat the bullet out for .020 to .030 jam and shoot you will have no problems.

 

[savagedasher]

Use your load but seat the bullet out for .020 to .030 jam and shoot you will have no problems.

That works for me I have jammed bullets and shot sort range 600yd targets and won. and have seen other do it also. Larry

 

[MrMajestic]

You are going to love the AI. As for how many times to fully form, you will know when it is difficult to close the bolt on a fired round. Start with just a handful of cases until you find that dimension. Remove the firing pin when testing case fit to remove that effect. Set up your size then to close without effort. The old fashioned method for an old dood! ;D

 

[savagedasher]

You will be able to look t the case if it has good well defined shoulder's the case is ready to work u a load. The reason your normal load works . Is when jaming a bullet you increase initial start chamber pressure . The reason I like ackley chambers or slows the brass from growing long. Larry

 

[Tommie]

I've never used (or heard of) an AI Go gauge. But since you're doing a pre-fit barrel on a Savage it's a moot point anyway.

Remove the firing pin from the bolt. Close the bolt. Stick a standard 223 GO gauge in the chamber and cinch the barrel barrel on. Double-check your work by chambering a few pieces of new brass. The bolt should close with a little more effort than "normal". It aint rocket surgery.

 

[SmokinJoe]

AI go gages are made, but to add a tidbit. When you look at one of these you are gonna swear that it's not the right grind because the shoulder angle will look too shallow. Don't know if it is actually a standard (parent brass) go gage or some shoulder angle that gives you the right crush, but they do work. You don't need a no go gage, though, just the go.

 

[MrMajestic]

What Joe said ^

 

[Deleted old_dood]

AI go gages are made, but to add a tidbit. When you look at one of these you are gonna swear that it's not the right grind because the shoulder angle will look too shallow. Don't know if it is actually a standard (parent brass) go gage or some shoulder angle that gives you the right crush, but they do work. You don't need a no go gage, though, just the go.

when I got the gauge that thought did occur to me.

 

[Deleted old_dood]

the barrel arrived today and I installed it. using the Manson 223ai go gauge and the regular 223 go gauge as my no-go worked exactly as some of you have posted. with the firing pin and extractor removed I did get a slight crush fit on unfired brass. I checked my OAL with some bullets I had and found the freebore to be much smaller than my original barrel. Where before, 60g FB bullets, loaded with about a .005 jam had about 1/8" bearing surface in the neck. with the new barrel, just touching the lands, the full bearing surface of the bullet is in the neck and even beyond. Does anyone suggest I use my original load of 24.8g IMR4895 or should I go lower when fireforming. Since the freebore is what it is, I'm looking forward to trying some 75g VLDs since I'd easily be able to jam them.

 

[Tommie]

No need to reduce the load. Load a round, pull the trigger and watch the magic happen.

 

[Deleted old_dood]

Fire forming and barrel break in went flawlessly. Some cases exhibited hard bolt lift on a load that wasn't anywhere near max. For some reason it looks like I'll have to bump the shoulder back on all cases. Wasn't expecting that. In addition almost all my cases measure 1.735 - 1.74 or less than the minimum length spec. Is all of this normal?

 

[Deleted old_dood]

And speaking about bumping back shoulders, will I be able to use my Hornady head space tool for this?

 

[MrMajestic]

Cases will come up short. You probably won't have to trim for a long time. You checked bolt, minus internals, closure on fire formed cases to determine headspace?