BRA project

[MDM]

I ordered a reamer from JGS back in February and it showed up last week. Its basically the popular print that seems to be floating around aside from being a .272 no turn. While waiting for the reamer, I got a set of Forster Dasher dies, knocked about .083 off the bottom of the sizer. I had a 6-47 barrel here that had 1200 rounds on it and was still shooting good, but was past the limit where I'd shoot it in a match, so I figured it would make a good fireforming barrel. So when the reamer showed, I had a forming barrel made up in a couple of hours.

Right or wrong, I set it up to a zero headspace fit on new BR brass. I ended up taking about .002 more off the base of the sizer to get a bump I was comfortable with. Fired brass looks good. Fire form barrel shoots 107s and 105h at .25" but the cheap 105 Hornady HPBT I got for forming pretty much suck, go figure.

This FF barrel is a .236/7tw Muller at 26". 29.7 Varget seems to be a good form load at 2850. The standard/go full power loads that most are using seem too hot in this form barrel anyway. 30.6 4895 rips are tiny hole at 2940, but Im getting a bit of pressure. 31.5 varget is too hot as well. I'm not gonna worry about it since this is just a form barrel and the new barrel will be a .237 bore 7.5tw at 28.

If anyone can give me a measurement with a Hornady headspace gauge on their fired brass, I'd appreciate it. This is my first Ackley go around and I'm curious if I got it right or not.

 

[Stan Taylor]

The reamer you got it would be interesting to see a print of the cartridge dimensions.

 

[Gilbert Garza]

Interested as well
I’m gonna do basically the same thing

 

[MDM]

Reamer print

 

[mikeeg02]

Yours is within .002" of mine at the .350 line on the shoulder, but our two comparators may not be identical. How much different is yours measuring from your print?

I can measure mine tonight, cant remember off the top of my head. Two of mine are the same, and one is a little different. Just how they ended up on the lathe.

 

[MDM]

Yours is within .002" of mine at the .350 line on the shoulder, but our two comparators may not be identical. How much different is yours measuring from your print?

I can measure mine tonight, cant remember off the top of my head. Two of mine are the same, and one is a little different. Just how they ended up on the lathe.

Using the B 350 comparator I'm at 1.174 on a twice fired pc. Seems I'm a little short.

 

[Stan Taylor]

Reamer print

That's a great combination you have there laid out very well.I like to form at 2750ish not hard on brass then tune after that the die sizing may not be enough if your bolt is a little sticky.

 

[Tim Singleton]

Is .244 diameter in the free bore what most are using?

 

[MDM]

I think so.

Interestingly enough, the Forster dasher sizer feels like its sizing more just based on the force required as compared to my other forster stuff in 6.5 and 6x47. Those size butter smooth with not much force required at all. The BRA requires 2x as much force but some cases can feel a little sticky when closing the bolt, even though I'm bumping the shoulders plenty. I suppose I'll send a few 2x fired cases to Harrels to have them pic one that will work best.

 

[mikeeg02]

Is .244 diameter in the free bore what most are using?

Mines a little smaller then that. I based it off my dasher print.

 

[mikeeg02]

Using the B 350 comparator I'm at 1.174 on a twice fired pc. Seems I'm a little short.

I want to say the last two digits on mine are ~64, I believe I am sizing to ~62, wherever the bolt consistently closed nice on the case. I can double check this evening. I have fired brass for all three barrels.

 

[Tim Singleton]

Mines a little smaller then that. I based it off my dasher print.

I know some are thinking more room is better. Just wondering if its trending that way. I use .2435 havent tried. 244

 

[mikeeg02]

I know some are thinking more room is better. Just wondering if its trending that way. I use .2435 havent tried. 244

My thinking is less likely to be affected by runout as there isnt really any room to runout. Could just be in my head. Ive personally never measured it, Im afraid if I measured it, I'd have to do something about it.

 

[Stan Taylor]

I think so.

Interestingly enough, the Forster dasher sizer feels like its sizing more just based on the force required as compared to my other forster stuff in 6.5 and 6x47. Those size butter smooth with not much force required at all. The BRA requires 2x as much force but some cases can feel a little sticky when closing the bolt, even though I'm bumping the shoulders plenty. I suppose I'll send a few 2x fired cases to Harrels to have them pic one that will work best.

That's a smart move they will do a good job.

 

[Stan Taylor]

I know some are thinking more room is better. Just wondering if its trending that way. I use .2435 havent tried. 244

I usually have mine specifically done at 243.8 because some bullets are fat at the pressure ring.

 

[Sheldon N]

If anyone can give me a measurement with a Hornady headspace gauge on their fired brass, I'd appreciate it. This is my first Ackley go around and I'm curious if I got it right or not.

I get fired brass at around 1.173 and size to 1.171-1.1715. Hornady .350 comparator, Forster FL Dasher die shortened about 0.085.

244 freebore diameter.

 

[mikeeg02]

With the hornady mine measure 1.176-1.178

With both of my .350 gauges that came with my Whidden dies 1.164-1.168

 

[MDM]

Ok, so we are close I'm at 1.174 sizing to 1.172 Thanks gents.

 

[Sheldon N]

The BRA requires 2x as much force but some cases can feel a little sticky when closing the bolt, even though I'm bumping the shoulders plenty.

Curious what you find out about not getting easy bolt close on cases which have been bumped 0.002. Have you tried marking them up with a sharpie and seeing where the case is contacting the chamber? You should get enough sizing at the base with a Forster, I average a bit over half a thou on mine.

 

[MDM]

I've marked a whole case with dykem and I'm not seeing anything out of the ordinary at all. In fact, it looks to be sizing cases perfectly at the 200 line and shoulder. I'm attributing it to too high of pressure on some test loads. I was getting ejector marks and sticky bolt on a standard 30g varget forming load and 29.6 4895 on a formed case was crazy stiff bolt at 2875fps. I had to go down to 28 varget to get to 2750 for forming where I saw absolutely no pressure signs. I'm not going to worry about it as this is just an old worn out barrel for forming. When I get the new Vector action soon, I'll put a fresh barrel on it and go from there. I've got 100 cases formed and will form another 200 on the break in of the new barrel and go from there.