Fire Forming-general questions

[D1gger]

So more of a general question about this process. I searched and really didn't come up with much here, and youtube videos are sketchy at best.
So my Dasher barrel is ready, and I have everything but the brass. I wanted to get some new Alpha, but who knows when that will come up again.
A local dealer has tons of new Norma 6BR brass. I know how fire forming works in general, but what's the best, most cost effective process? I don't want to burn up varget or 105's if I don't have to. I've heard about using corn starch, but I know nothing about that.
Any suggestions would be appreciated!

 

[Gohring65]

I would buy some cheap bullets and jam them in the lands with a minimum charge weight. It helps prevent stretch just above the web area.

 

[Greenmoustache]

So more of a general question about this process. I searched and really didn't come up with much here, and youtube videos are sketchy at best.
So my Dasher barrel is ready, and I have everything but the brass. I wanted to get some new Alpha, but who knows when that will come up again.
A local dealer has tons of new Norma 6BR brass. I know how fire forming works in general, but what's the best, most cost effective process? I don't want to burn up varget or 105's if I don't have to. I've heard about using corn starch, but I know nothing about that.
Any suggestions would be appreciated!

I have done quite a bit of experimenting with my 6 Dasher and am on my second barrel now. I tried both Alpha OCD Dasher brass and fireforming Lapua 6BR. While I can’t speak to the Norma brass I can say I do prefer the Lapua over the Alpha even with the additional steps of fireforming.

My process is 28gr of AA4064 or IMR 4166 (both readily available at least for me locally), load whatever 105-108gr projectile I can find the cheapest .030” into the lands and that’s it. I have blow lengths within .001” and out of 505 pieces I’ve only had two split necks.

I anneal the brass after fireforming and resize and then load to my normal 32gr Varget w/ Berger 105 dasher load. Shoots ~.25 MOA with SDs around 5fps.

That all said, the Alpha brass is fine it just hasn’t always been available and I have yet to run into any issues finding Lapua BR brass. I’m up to about 10 firings on my first batch of 100 now and no issues.

 

[D1gger]

I do have some random 105-115 gr 6mm's laying around, I could go that route. Some older Winchester primers that I really don't use for anything these days. That will work-Thanks!

 

[spife7980]

Before you buy the norma brass... do you have the chamber for the norma brass or the lapua brass? They arent the same.

Reason being that the norma brass had different rim thickness (not consequential to the rifle but it is to the shell holder for reloading) as well as a much longer neck that needs to be trimmed back liek .1 if you are going to stick it in a lapua chamber. Also the norma brass doesnt handle the same pressures as lapua so if you try to use the same load data youll blow the pockets out.

Generally people think of the norma dasher brass as crap. I didnt even realize they have made it in the last few years, thats how lityle attention it garnered for all of its issues.

Id wait for the lapua brass myself but the alpha wouldnt be the worst choice (again depending entirely on your specific reamer). They do make an alpha dasher reamer but Ive seen people use alpha in a lapua dasher chamber too so I guess they just deal with barely any neck clearance and dont load at the top end of pressures.



The best way to fireform is to false shoulder, size the neck up to 25 or 6.5 cal with a mandrel and you will see that they no longer chamber becasue the case neck is larger than the chamber neck. Then using the sizing die size the necks partially back down just far enough so that you can chamber them but still feel the unsized neck contacting the chamber which ensures that it is pressed back against the bolt face so it doesnt stretch on the wrong part of the case when you fire it. Then seat the bullets to jam as a second insurance of proper case growth. You want the shoulders moving, not the case webbing at the base.

Fireforming isnt a waste of barrel life or components at all and will rival the formed pieces. Stick the 105-115gr bullet over 30gr of varget and it will still shoot well enough to win a match.

 

[D1gger]

Good to know about the chambers. I'll ask when I pick it up from Hawk Hill, but I feel like it's a Lapua chamber. Shawn mentioned Lapua brass would be best if it can find it. I have found some Lapua 6BR brass that I'll probably go with and form it up from there.

 

[Gohring65]

Fireforming is also a good way to get rounds down your barrel to get it to the 150-200 round threshold where it speeds up and stabilizes.

 

[Islas82]

Joining with a different question, I know all barrels arent the same. I got some 6CM lapua brass 5x fired that were used on a proof barrel SAMMI spec chamber, am about use them on a new proof SAMMI spec chamber do you guys think I have to fire 2-3 times again before load development? Or maybe I can do one and go?

 

[Digger83]

Get the Lapua brass, use whatever random bullets you have laying around and jam them .030 into the lands with 30 grains of Varget and a soft primer and break the barrel in and get some good practice. I have a bunch of cheap Hornady 105s bought years ago I keep just for this purpose. They shoot surprisingly well. Every time I go out to my range I run a couple of mags of fireforming loads as barricade practice. Might take me all year but I will get thru my stack of new Lapua brass before I wear out the brass I currently shoot matches with.

 

[b6graham]

Joining with a different question, I know all barrels arent the same. I got some 6CM lapua brass 5x fired that were used on a proof barrel SAMMI spec chamber, am about use them on a new proof SAMMI spec chamber do you guys think I have to fire 2-3 times again before load development? Or maybe I can do one and go?

no but you want 100-200 rounds on the barrel first before load development

throw a few charges together to find what's safe. and find the speed you want. load them all up and shoot

my new strategy. 500 pieces of brass. 2 identical barrels
put ~250 through each barrel with a mostly random charge (its dasher so 31.5gr varget. starts at 2870 from virgin barrel and will speed up)
then load develop/confirm speed with the 500 pieces once fired brass

 

[Rocketmandb]

Joining with a different question, I know all barrels arent the same. I got some 6CM lapua brass 5x fired that were used on a proof barrel SAMMI spec chamber, am about use them on a new proof SAMMI spec chamber do you guys think I have to fire 2-3 times again before load development? Or maybe I can do one and go?

Just note that different chambers, different reamers (even the same) can potentially cause extraction issues when exchanging brass. If the new chamber is smaller than the old by even a tiny amount, it can cause problems. Be prepared.

 

[earthquake]

I'm about to start this process with a bunch of 1x fired Lapua BR brass. I have a bunch of Hornady 105's I got off a prize table and a big jug of IMR 4166 I don't use for much. I'm going to try the 0.030" jam method w/o the false shoulder. A good friend did it that way with his Dasher to good effect. The false-shoulder method seems way too complicated and time consuming. Maybe if I was shooting benchrest I'd look more into that....maybe.

My question for anyone else who did it this way: What neck tension are you shooting for? More? Less?

I have neck bushings in 0.266" and 0.267" to work with.

Thanks!

 

[Rocketmandb]

I'm about to start this process with a bunch of 1x fired Lapua BR brass. I have a bunch of Hornady 105's I got off a prize table and a big jug of IMR 4166 I don't use for much. I'm going to try the 0.030" jam method w/o the false shoulder. A good friend did it that way with his Dasher to good effect. The false-shoulder method seems way too complicated and time consuming. Maybe if I was shooting benchrest I'd look more into that....maybe.

My question for anyone else who did it this way: What neck tension are you shooting for? More? Less?

I have neck bushings in 0.266" and 0.267" to work with.

Thanks!

What are you fire forming to?

 

[D1gger]

So I just finished doing this. I don't think neck tension is going to make any difference. I jammed it into the lands and ran 28gr of 4166. It shot great groups, but it was slow, like 2650's. Brass looks good too. I would say whichever bushing holds the bullet the best!

 

[Mike Casselton]

So I just finished doing this. I don't think neck tension is going to make any difference. I jammed it into the lands and ran 28gr of 4166. It shot great groups, but it was slow, like 2650's. Brass looks good too. I would say whichever bushing holds the bullet the best!

Ignore the neck tension if you're fire forming and jammed. It won't make any difference.

What are you fire forming to?

I'm gonna bet it's a Dasher.

 

[earthquake]

What are you fire forming to?

Dasher