6BRX Fireforming

[Ackman]

6 BRX FIREFORMING

I've always fireformed improved cartridges with a pretty good crush. I did some 6BR into 6BRX with 70TNTs and a heavy .030"-.040 jam. The cases formed perfectly. I now have some cases necked to .257 with a false shoulder, gonna try those. Is there any reason to choose one over the other?

 

[JEFFPPC]

I turn the necks forming a shoulder that is cut just about .010 into the newly formed shoulder along with a bullet jammed hard. No oil, dry case and clean dry chamber. I have done several thousand over the yrs. This gives me the longest cases, no donut issues, AND no cases stretched in the web area. I have tried several other methods and discarded them. I am left with great 6BRX cases. After two or three firings I run the neck turner back over them. I anneal after every firing, forever.

 

[swimster]

I have done it both ways. 1 batch I formed with Jam fit didn't work to well because i didn't use enough neck tension. Last batch i fired were for my 22 BRX. I neck turned the 6 Br case to the neck shoulder junction fo 12 thou. I have a tight neck chamber. Then ran it through my 22Brx die for a crush fit on the false shoulder. Only lost 1 case in that batch of 200. I tried the oat meal method too ended up with particaly formed cases plus it is pretty messy.

 

[Ackman]

Thanks Jeff and swimster. From now on I'll be using the false shoulder. Mine is an unturned chamber (.272 I believe, but it wasn't my reamer) and at .257 there's enough shoulder to feel it. Never needed to use bullet jam forming AI cases but here it seems like also a good idea. The heavy jam method worked well for the few I formed, but it was combined with a very hard seat and bolt pressure was considerable. A concern is to not lose case length and I didn't know which would leave them the longest.
*** Mine are varmint guns and shoot lighter bullets, they're only put on paper for load workup.

 

[jr600yd]

Like Swimster I’ve done it both ways but got better results using a false shoulder. This is what I do and why.
Like you my rifle has a 272 neck so their is no need to neck turn.
First I expand the necks to 6.5 (because this is what I have) then using a bushing die resize the neck about half way to 6mm. Sized just enough that I can close the bolt with a tiny amount of resistance. Since I shoot F Class I load them with 107 SMK’s and shoot them in 600yd match.

The reason is this:
My BRX uses a Remington action. My bolt has a good ejector spring. Using the “Jam” method requires quite a bit of neck tension to overcome the ejector spring. I’ve found the “Jam” method, in my rifle, does not fit my chamber very well and fire formed cases are not consistent in size or length. You could remove the ejector, plug the hole and use the “Jam” method but I found it more work than it was worth.

 

[brxbrad]

I've been shooting a BRX for 10 years now and found the false shoulder method is what I prefer. I always get the same results when I pull the trigger. I fire form with 30 grains of Varget and a 105 hybrid. I fire form them at club matches with good results.

 

[comagutsa]

I've fire formed with 030 jam. 005 neck tension and 30gr of 2208/varget no worries for a few barrels but after a few blow outs on primers I now hydro form all Amy 6BRX brass.. And while forming them I use this time to test loads and bullets to see what my barrel likes. 2 birds with one stone thing. I also run a 270 neck so I turn my 6BR brass all the way down to shoulder before I hydro form

 

[JEFFPPC]

It's not necessary to cut back into the should that far. I only turn so I am in the shoulder maybe .005. I have never blown primers , maybe .5 gr less powder or so in your fireform .loads will end that. I don't know what weight bullet is in your photo, your way down past the neck shoulder junction into powder space, if it's a long range bullet.. If that is the case you need to have your barrels throated to keep the pressure ring of the bullet above that point. If your seating the pressure ring below that point and get a hint of a donut you have no neck tension control. I do not understand why you feel the need to hydro form.Give your smith a dummy round with the pressure ring half down the neck and have him throat it so the lands make a tiny mark on the bullet. Now you have established touch in can go in and out to determine what your barrel and reamer like.

 

[comagutsa]

Jeff these pics were from a few barrels ago. I now run a 150FB so I'm out now.
But I hydro form now and I enjoy it.. blown a primer and it broke my trigger, never again as it cost me a heap as I needed a new trigger asap for comp the next week and nobody had parts for it in Australia.
I won't take the chance anymore.. I did 400 cases FF before I had blown primer and that's all it took to stuff my trigger ..
Stuart

 

[Webster]

6 BRX FIREFORMING

I've always fireformed improved cartridges with a pretty good crush. I did some 6BR into 6BRX with 70TNTs and a heavy .030"-.040 jam. The cases formed perfectly. I now have some cases necked to .257 with a false shoulder, gonna try those. Is there any reason to choose one over the other?

I have a 6BRX. I keep it simple. Just.a light jam and shoot. Under .400’’ groups FF.

 

[JEFFPPC]

I have a 6BRX. I keep it simple. Just.a light jam and shoot. Under .400’’ groups FF.

That works well.

 

[swd]

I shoot 30.5 of Varget with a Sierra 107SMK at hard jam. Take the ejector out if it has one and I use a soft primer like a Winchester for fire forming. It runs about 2760+/- in long barrels. Take it to a mid range match and they shoot stupid good.

 

[Ackman]

Like Swimster I’ve done it both ways but got better results using a false shoulder. This is what I do and why.

My BRX uses a Remington action. My bolt has a good ejector spring. Using the “Jam” method requires quite a bit of neck tension to overcome the ejector spring. I’ve found the “Jam” method, in my rifle, does not fit my chamber very well and fire formed cases are not consistent in size or length..

This.
Most of my rifles have AI chambers and I've fireformed many thousands of rounds. All of them with a good bit of crush and all are formed perfectly. This BRX is new to me and I've read where some target shooters have good results blowing that shoulder forward just using a heavy jam. It's an easier way to go. I tried it with a few cases and they formed nicely but as you said, case length is literally all over the place. A huge variation. These will need trimming and more important, that length has to come from the case body. Thus my curiosity about whether or not using just a heavy jam was common practice. I've done a few with a .257 shoulder and formed length still varies a bit, but they're much more uniform.

 

[swd]

This.
Most of my rifles have AI chambers and I've fireformed many thousands of rounds. All of them with a good bit of crush and all are formed perfectly. This BRX is new to me and I've read where some target shooters have good results blowing that shoulder forward just using a heavy jam. It's an easier way to go. I tried it with a few cases and they formed nicely but as you said, case length is literally all over the place. A huge variation. These will need trimming and more important, that length has to come from the case body. Thus my curiosity about whether or not using just a heavy jam was common practice. I've done a few with a .257 shoulder and formed length still varies a bit, but they're much more uniform.

Both ways skin that cat. The way that works better for you is the way to go. Don’t think anymore about it.

 

[JohnMill]

Like Swimster I’ve done it both ways but got better results using a false shoulder. This is what I do and why.
Like you my rifle has a 272 neck so their is no need to neck turn.
First I expand the necks to 6.5 (because this is what I have) then using a bushing die resize the neck about half way to 6mm. Sized just enough that I can close the bolt with a tiny amount of resistance. Since I shoot F Class I load them with 107 SMK’s and shoot them in 600yd match.

The reason is this:
My BRX uses a Remington action. My bolt has a good ejector spring. Using the “Jam” method requires quite a bit of neck tension to overcome the ejector spring. I’ve found the “Jam” method, in my rifle, does not fit my chamber very well and fire formed cases are not consistent in size or length. You could remove the ejector, plug the hole and use the “Jam” method but I found it more work than it was worth.

Hey jr600, you could also remove the ejector and not plug the hole.It's just fireforming.Don't think you'll flow much brass with that load.

 

[jr600yd]

I don’t know John, I usually fireform with 30grs of Varget. Guess I could do as you suggest?

 

[JohnMill]

I don’t know John, I usually fireform with 30grs of Varget. Guess I could do as you suggest?

You could. It also helps when you are trying to get a good read on seating depth. ( just in case other published methods don't work for you
John