Trouble with the bra

Matt_3479 · Aug 2, 2021

So I got a 6bra about 2-3 weeks ago and just firing forming the brass. I have never experienced so many light strikes/failure to fire. At first I thought maybe not deep enough primers. Pushed them in further and it got worse. I’m assuming cause I’m touching lands and not Jamming so it’s allowing the case to shift when firing pin is being struck? Is this what Most would assume?

on the good side, it’s bloody accurate when it does fire lol. 0 load development, new brass, 0 work

Pvt.Donut · Aug 2, 2021

I know in some fireforming the false shoulder helps keep the case against the boltface to prevent light strikes. That shouldn't be an issue with the BRA since a BR case should fit the same or snug in the BRA chamber. Your primers should be seated against the anvil, however deep that needs to be. If the issue resolves with fireformed brass I guess you don't need to worry, but it's probably something with the fireforming.

b6graham · Aug 2, 2021

any reason you arent jamming?

Matt_3479 · Aug 2, 2021

Pvt.Donut said:
I know in some fireforming the false shoulder helps keep the case against the boltface to prevent light strikes. That shouldn't be an issue with the BRA since a BR case should fit the same or snug in the BRA chamber. Your primers should be seated against the anvil, however deep that needs to be. If the issue resolves with fireformed brass I guess you don't need to worry, but it's probably something with the fireforming.

Yah I’m debating on loading up the ones that have fire formed, and seeing if the problem occurs. If not then I obviously know it’s the fireforming loads.

kriller134 · Aug 2, 2021

I just started with a bra last month. I’m jamming it .010” and haven’t had any issues. I also didn’t expand the necks. Maybe pull the ones that didn’t fire and reseat them longer?

JBoomhauer · Aug 2, 2021

The 6BRA should be headspaced .004 short with standard gages to minimize this issue. The alternative is to jam the bullet. If there is light primer strikes, it’s prob set to regular br headspace. Once fireformed it should be fine, as long as you don’t size it back down too much.

Matt_3479 · Aug 2, 2021

b6graham said:
any reason you arent jamming?

Well I loaded 50 at touching 50 at .010 thou longer and I hit pressure so seated them back.

I wouldn’t mind going over jam actually. Cause you have jump which is obvious. You have touching/kissing which I fully understand as well. But when does jam come into play? Is jam anything past touching/kissing? Cause watching the Cortina method on finding jam and it’s significantly longer then touching/kissing?

kriller134 · Aug 2, 2021

Matt_3479 said:
Well I loaded 50 at touching 50 at .010 thou longer and I hit pressure so seated them back.

I wouldn’t mind going over jam actually. Cause you have jump which is obvious. You have touching/kissing which I fully understand as well. But when does jam come into play? Is jam anything past touching/kissing? Cause watching the Cortina method on finding jam and it’s significantly longer then touching/kissing?

Jam is when you’re actually into the lands

Milo 2.5 · Aug 2, 2021

CCI 450's?

Matt_3479 · Aug 2, 2021

Milo 2.5 said:
CCI 450's?

Yes

kriller134 said:
Jam is when you’re actually into the lands

So anything past touching the lands is considered a jam then? So with my current fire forming load touching, If I bumped them forward .010 thou I’d be jammed .010 thou? Like I said when I used the Erik cortina jam point method it was much further then this

JBoomhauer · Aug 2, 2021

So you are jammed further than the cortina jam method? How’s neck tension?

kriller134 · Aug 2, 2021

Matt_3479 said:
Yes

So anything past touching the lands is considered a jam then? So with my current fire forming load touching, If I bumped them forward .010 thou I’d be jammed .010 thou? Like I said when I used the Erik cortina jam point method it was much further then this

I’m not familiar with the cortina method, but yes anything longer than your touching point will be jamming. Look at how long my coal is. That’s because I’m .010” into the lands.

Matt_3479 · Aug 2, 2021

JBoomhauer said:
So you are jammed further than the cortina jam method? How’s neck tension?

Neck tension is .002 thou. I am just touching lands not jammed at all. When I first did the cortina method on this cartridge it was so so long I though maybe I should back it off a bit. So I went back stripped the bolt ( firing pin, ejector) and pushed the bullet back until 0 resistance and called that/.001 thou more touch point and loaded there. My question was so at my touch point, anything longer then this would be considered jam? I know how dumb that sounds but watching cortina’s video years after always knowing this to be jam, and he explains and shows finding jam and it’s significantly longer then .010 longer then touch point.

918v · Aug 2, 2021

What if you run the cases into a 308 Small Base die. That’s going to pop the shoulder forward, maybe enough to stop the light strikes.

kriller134 · Aug 2, 2021

.010 is arbitrary. You can jam as much or as little as you want.

JBoomhauer · Aug 2, 2021

I don’t remember his method fully, I recall it’s when your bullet stays in the rifling rather than just being marked up. Low neck tension will slip much sooner than high tension. This might not be good for fireforming if you have a longer headspace.

With prefits nowadays I just carefully drop a bullet into the chamber of a loose barrel and measure to the back with a depth mic. Only force is gravity. I do a little figuring and have my touching lands number. “Jam” to me is anything further into the lands than touch, same as your thoughts.

jakelly · Aug 2, 2021

You can only jam up to around 0.017”. After that you will not be able to close your bolt.

spife7980 · Aug 2, 2021

jakelly said:
You can only jam up to around 0.017”. After that you will not be able to close your bolt.

Bullshit (depending on interpretation of jam vs engraving point). I used do false shoulder in addition to jamming with them to seated .2 long from touch for dasher forming. It’s a bit tough so I backed down to .1 now. Sure it sets back a bit but it’s not insurmountable at all.

Milo 2.5 · Aug 2, 2021

Matt_3479 said:
Yes

So anything past touching the lands is considered a jam then? So with my current fire forming load touching, If I bumped them forward .010 thou I’d be jammed .010 thou? Like I said when I used the Erik cortina jam point method it was much further then this

You should not have to jam to FF BRA Brass. Switch to to a CCI 400 or Federal 205, softer cup primer to get your brass fired, then go back. Shoot accurate loads and have fun fireforming.

Matt_3479 · Aug 2, 2021

JBoomhauer said:
With prefits nowadays I just carefully drop a bullet into the chamber of a loose barrel and measure to the back with a depth mic. Only force is gravity. I do a little figuring and have my touching lands number. “Jam” to me is anything further into the lands than touch, same as your thoughts.

I’ve some what seen this talked about before, would you be able to go into more depth here. I don’t know if I fully understand how you determine once bullet has stopped, how to get a measurement from that point to your case measurement.

JBoomhauer · Aug 2, 2021

Matt_3479 said:
I’ve some what seen this talked about before, would you be able to go into more depth here. I don’t know if I fully understand how you determine once bullet has stopped, how to get a measurement from that point to your case measurement.

Sure it’s gonna take a minute though.

Matt_3479 · Aug 2, 2021

I’m actually struggling more with this caliber then any other caliber I’ve loaded for. To double check everything be now pulled the bolt out, removed firing pin and ejector again, and started over with a fresh piece of brass to find touch point. This rifle is on an impact acrion, and for the life of me I can not get a consistent measurement.

Doing the cortina method the bullet just keeps getting stuck.

Doing what I’ve always done by seating 10 thou at a time until I get close move in by .002 at a time until bolt closes with no effort, but I cannot seem to get a consistent reading

spife7980 · Aug 2, 2021

What’s your firing pin protrusion and how much overall travel do you have? An impact guy should be able to confirm it it’s right or not. If that’s reasonable what are your before and after case measurements?
I’d bet a fed205m would be more likely to set off but I don’t think you should have to. The answer should be somewhere in the numbers.

Matt_3479 · Aug 2, 2021

Well I may have finally got it. When seating back slowly I found that 1.1863” to be where bolt closed with ease the first time I did it (last week) tn I noticed that slight click when opening and started again. When moving in slowly I got to 1.870 and it was slight pressure on close and when I opened back up I dropped the bolt and it closed without any hesitation. I measured and it read 1.870” so I started questioning. I moved back to 1.890 and it closed with resistance but pushed the bullet into 1.8885. I put the same one back in, and it pushed it back to 1.885, then again to 1.882 and then I cycled 4-5 times and it stopped at 1.881. The is the absolutely slightest resistance for the first close then if cycled a second or third time it drops free. So I believe 1.881 is my actual touch point. There is still a click at the top but was told that is something to do with impacts and not too worry about it. If this is the case, I would of been .018 thou from touch which may be causing my light strikes

JBoomhauer · Aug 2, 2021

M#1. Measure back of bullet to barrel face. 1.0305

M#2. Measure barrel face to shoulder. .888

M#3. Measure Receiver face to bolt face. 1.0255 (with recoil lug in place if separate)

(M1-M2)+M3= Bolt face to back of bullet. 1.168

Use a comparator to get back of bullet to ogive. .653

Add that number and you have Bolt face to Ogive. 1.821

Or… use the 1.168 + bullet length 1.277 to get oal 2.445.

These numbers are from a barrel that’s about worn out so it’s prob a bit on the long side. You can call it the Dan method. All numbers no “feel”.

I Doubt it will catch on.

JBoomhauer · Aug 2, 2021

Matt_3479 said:
Well I may have finally got it. When seating back slowly I found that 1.1863” to be where bolt closed with ease the first time I did it (last week) tn I noticed that slight click when opening and started again. When moving in slowly I got to 1.870 and it was slight pressure on close and when I opened back up I dropped the bolt and it closed without any hesitation. I measured and it read 1.870” so I started questioning. I moved back to 1.890 and it closed with resistance but pushed the bullet into 1.8885. I put the same one back in, and it pushed it back to 1.885, then again to 1.882 and then I cycled 4-5 times and it stopped at 1.881. The is the absolutely slightest resistance for the first close then if cycled a second or third time it drops free. So I believe 1.881 is my actual touch point. There is still a click at the top but was told that is something to do with impacts and not too worry about it. If this is the case, I would of been .018 thou from touch which may be causing my light strikes

Nah 1.8885 is more likely your number with your initial neck tension. As you pulled the bullet out and pushed it back in repeatedly, you lightened the tension. This is why the numbers crept lower and lower every time.

JBoomhauer · Aug 2, 2021

Nevermind on the neck tension comment in the previous post, I read it as if you were using a bullet puller to pull back out to the initial 1.890 number before closing the bolt again. Still would go with the 1.8885 number though.

B y r o n · Aug 2, 2021

I have no experience with the BRA and have only fire formed 300 BLK from military 5.56 brass. I assembled the pistol it would be fired in and head spaced the bolt to verify it was within spec. To prevent case stretch I trimmed the brass to max length since I knew it had to blow out the shoulder to the desired form. I did this figuring the case mouth would seat against the end of the chamber like a pistol cartridge. I figured this would keep the base/primer where it should be when it went off and allow the shoulder to form with minimal stretch. No sense to start a pre mature case separation. No issues with light strikes or failure to fire and perfectly formed brass.

As previously mentioned, if your barrel and bolt headspace properly, have you checked your firing pin protrusion?

jakelly · Aug 3, 2021

spife7980 said:
Bullshit (depending on interpretation of jam vs engraving point). I used do false shoulder in addition to jamming with them to seated .2 long from touch for dasher forming. It’s a bit tough so I backed down to .1 now. Sure it sets back a bit but it’s not insurmountable at all.

You’re closing your bolt on .100” and .200” of jam? I don’t know how you’re measuring, but that’s not right.

OREGUN · Aug 3, 2021

The case should headspace on the shoulder without needing any “jam” from a false shoulder or the bullet. Are we still talking about failure to ignite/light primer strikes? There’s no net effect from seating depth at all in the first firing with standard BR brass…the case is a .004” crush fit between the bolt and the chamber shoulder. If it isn’t, your chamber is too long and you should have a chat with your gunsmith. The bolt should have a little resistance on closing, even on an empty case. It’s one of the beautiful things about fireforming the BRA. There really no risk of accidentally getting stretch in the web instead of a new shoulder shape. If you are getting “light” primer strikes it’s because your firing pin protrusion is a tad short or a little light or MAYBE your primers aren’t quite seated fully against the bottom of the pocket although this is less of a problem than the interwebs might lead you to believe, in my experience. Maybe a softer cup primer for fireforming is needed. Try 400s. All this discussion of measuring your distance to the lands is cool but isn’t really germane to the fireforming discussion for BRA.

spife7980 · Aug 3, 2021

jakelly said:
You’re closing your bolt on .100” and .200” of jam? I don’t know how you’re measuring, but that’s not right.

But it is.
It’s no more incorrect than your arbitrary .017 figure.

Only I’ve done it. .2 hurts your wrist after 100 rounds. Lube your lugs. That’s why I dropped back to .1 which is still tough but not impossible.

Matt_3479 · Aug 3, 2021

JBoomhauer said:
Nevermind on the neck tension comment in the previous post, I read it as if you were using a bullet puller to pull back out to the initial 1.890 number before closing the bolt again. Still would go with the 1.8885 number though.

So I grabbed 4 fresh cases and check to see if I had .002 neck tension if not I sized the neck to insure this. Loaded 1 at 1.888, 1 at 1.885, 1 at 1.883 and 1 at 1.882.

The first one got pushed back too 1.8835, and the last 3 moved into 1.8815 area. I put the first back in and it pushed back to 1.8815 as well. I then cycled each one 1 more time and they all settled at 1.881” and that’s why I figured touch point to be 1.881-1.882

JBoomhauer · Aug 3, 2021

That sounds reasonable.

A couple questions. Do you have headspace gages for the bra? If not, with fresh brass do you feel any resistance closing the bolt? If not, How many pieces of scotch tape can you put neatly on the case head before you feel resistance?

Matt_3479 · Aug 3, 2021

JBoomhauer said:
That sounds reasonable.

A couple questions. Do you have headspace gages for the bra? If not, with fresh brass do you feel any resistance closing the bolt? If not, How many pieces of scotch tape can you put neatly on the case head before you feel resistance?

I do not have head space gauges for the bra unfortunately. I have the bolt still stripped so when I get home I will put a fresh piece in and see if there is resistance. I noticed on every couple shots it seems more difficult to close (like I was jamming which clearly I wasn’t) so it makes me think my headspace might be a touch long. I will double check tn with a fresh piece.

I did check shoulders on the fire formed ones, and tried throwing it in with high resistance, then bumped back exactly .002 thou and there’s still resistance which I thought was odd.

LR1845 · Aug 3, 2021

jakelly said:
You’re closing your bolt on .100” and .200” of jam? I don’t know how you’re measuring, but that’s not right.

i shot several BRX barrels and you HAVE to jam hard or you have issues...i jammed .125 with no issues....the bullet just get pushed back into the case just as if you were seating on your press.

@Matt_3479 you should NOT have to jam a BRA to fire form..as someone stated above an AI cartridge is -.004 so the shoulder of the case holds it tight when fire forming...im on barrel #5 in BRA and run CCI450s when fire forming never an issue...sounds to me like you do not have enough firing pin fall..a weak FP spring or possibly head space issue.

Matt_3479 · Aug 3, 2021

LR1845 said:
i shot several BRX barrels and you HAVE to jam hard or you have issues...i jammed .125 with no issues....the bullet just get pushed back into the case just as if you were seating on your press.

@Matt_3479 you should NOT have to jam a BRA to fire form..as someone stated above an AI cartridge is -.004 so the shoulder of the case holds it tight when fire forming...im on barrel #5 in BRA and run CCI450s when fire forming never an issue...sounds to me like you do not have enough firing pin fall..a weak FP spring or possibly head space issue.

Okay thank you. So to eliminate these issues how to I proceed from here. This gun is used, and the previous owner had been excellent to deal with and has provided me with every piece of information possible and he hasn’t had these issues before.

So moving forward from here, checking headspace to start I should load and empty 6br case. If there isn’t any pressure then it’s a head space issue? If there is a bit of a crush fit then we can eliminate the headspace question? The firing pin/firing pin spring. I inspected jt and there doesn’t seem to be any damage to the firing pin itself so spring might be light?

I’m just looking to go through the steps to see where to proceed and how to move forward from here. 2 range trips and over 25-35 light strikes/failure to fire makes for a very frustrating time lol.

So start with

1.) check empty new piece of brass for pressure on close. If none, headspace issue. If there is, should be good to go.
2.) jam bullet to help insure
3.) switch primers to see if it’s just the hard cup, and try 450’s once brass has been formed

If I can make it through all this headache and it happens to be a very slight headspace issue, but the all the brass has been fire formed at this point. I should be good to proceed without issues from this point technically. Or should I still address the headspace problem? Wondering cause once fireformed my new brass matches chamber spec, and I just bump back and bang away correct?

JBoomhauer · Aug 3, 2021

If it is a headspace issue the “right” answer is to have a gunsmith rechamber it.

The second option if headspace is slightly off is to Jam and essentially create your own wildcat. Call it a BRA+ or whatever, but it’s no longer a bra and just know what you have. The 205 primer suggestions would help if this is the route you want to go.

I personally would rechamber if the headspace is off.

Milo 2.5 · Aug 3, 2021

JBoomhauer said:
I personally would rechamber if the headspace is off.

Not in 100% agreement here. If he can FF his brass, it is what it is. He can set his dies accordingly, his numbers are his numbers.
I fired 500 pcs of perterson dasher brass that grew .010" in length, shoulder datum length, not OAL. Friggin pain, and the chamber was not oversized, now the brass is ready to go, for however long it lasts. I put up with all this BS to have dasher brass with case capacities .2gr more than a 6 BRA.

OREGUN · Aug 3, 2021

I have a Borden action in BRA that occasionally fails to ignite during FF. My impact, never. I’ve always attributed it to the Borden having a very “controlled” firing pin for lack of a better way to say “as light as possible and with as little movement as possible”. Come to think of it though, I was using 450s with the Borden and BR4s with the Impact so maybe it’s a cup difference. In both action/barrel combos, there is resistance on a new brass.

-check to see if there’s some resistance on bolt close with your stripped bolt and a fresh 6BR case.
-it won’t hurt anything to jam the bullet too, assuming your charge isnt hovering right on the edge of “blow your face off”. —What’s your powder charge and type?
-since the bolt is stripped, make sure to clean and lightly lube the firing pin and spring. It would surprise me if an impact had a firing pin spring or protrusion issue but it could be dirty or damaged which could cause erratic pin fall.
-I would expect this problem to go away entirely with fireformed brass at which point, yes, re-size to your liking and shoot.
-anywhere near Denver/southern WY? I have BRA headspace gauges you can borrow if you want to satisfy your curiosity.

as for “finding the lands”. I use a bullet puller and work “out” until I see the marks where the Bullet starts to touch. I’ve never had repeatable results letting the bolt push the bullet in on close…usually the bullet is then stuck in the lands and gets pulled back out on extraction. So, I use a normal case with regular tension, seat a bullet, chamber and extract, look for engraving. Seat slightly deeper, or pull the bullet and seat longer, as needed, wipe the marks off with scotch-brite and repeat. Not sure whose method that is but it’s worked better for me than the “split a case neck” method or trying to “feel” when the bullet first touches something or trying to take 10 super precise measurements and add/subtract to get to a number that theoretically makes sense.

JBoomhauer · Aug 3, 2021

Milo 2.5 said:
Not in 100% agreement here. If he can FF his brass, it is what it is. He can set his dies accordingly, his numbers are his numbers.
I fired 500 pcs of perterson dasher brass that grew .010" in length, shoulder datum length, not OAL. Friggin pain, and the chamber was not oversized, now the brass is ready to go, for however long it lasts. I put up with all this BS to have dasher brass with case capacities .2gr more than a 6 BRA.

I get that. My reason is that I have multiple BRA barrels cut with the same reamer and same headspace. I wouldn’t want to keep track of which brass goes where.

Milo 2.5 · Aug 3, 2021

JBoomhauer said:
I get that. My reason is that I have multiple BRA barrels cut with the same reamer and same headspace. I wouldn’t want to keep track of which brass goes where.

I surely get that too, sounds like the OP is rather new to this shit though.
He has received some solid advice and tips, once his brass is FF, he can move on, we are complicating things to an extent.

JBoomhauer · Aug 3, 2021

Milo 2.5 said:
I surely get that too, sounds like the OP is rather new to this shit though.
He has received some solid advice and tips, once his brass is FF, he can move on, we are complicating things to an extent.

Always do, we can’t help it

OREGUN · Aug 3, 2021

Here’s some good info and a drawing from our friends over at accurateshooter regarding the Ackely Improved process. Surely there’s a range of acceptable headspace dimension for BRA and if the previous owner/shooter was not having the same issue, it seems unlikely to be a chamber that needs to be re-cut. I’m certain of the headspace dimension in my Borden actioned BRA at it still occasionally fails to fire during fireforming with 450s.

Kinetic Moose · Aug 3, 2021

I have some friends that are switching to this because it's just no brainer consistency and accuracy. personally if barrels were in stock I would swap in a heartbeat as well.

What action are you running? I have had light primer strikes with some actions and it usually ended up being dirt somewhere, however thisguy had some issues with spring tension because he swapped triggers and the setback of the sear was different I think only .030 and it was on the ragged edge.. Might want to try a different trigger or talk to your action maker and see what clicky thingy they recommend. Joel over at terminus actions has a lot of knowledge on this that I picked up through osmosis when my buddy when through it.

Baron23 · Aug 3, 2021

JBoomhauer said:
M#2. Measure barrel face to shoulder. .888

Pardon my ignorance, but exactly how did you take this measurement?

JBoomhauer · Aug 3, 2021

Baron23 said:
Pardon my ignorance, but exactly how did you take this measurement?

Depth mic sitting on barrel face as pictured above, but measuring down to the shoulder instead of the back of the bullet. It’s essentially tenon length.

JBoomhauer · Aug 3, 2021

Baron23 said:
Pardon my ignorance, but exactly how did you take this measurement?

Here’s my spreadsheet for another gun. Might help visualize.

jakelly · Aug 3, 2021

OP,
Most of the potential causes of your problem are listed here.
If you want to check your chamber for a .003” or .004” crush fit, you can blacken a new case shoulder with a lighter and close the bolt. If you’re getting the crush there will be a ring below the neck. If you don’t get a brass ring, you can add a piece of tape on the cartridge head to determine what your headspace is on new brass.

Kinetic Moose · Aug 3, 2021

Take a piece of scotch tape place it across the rear of an unfired shell, does the bolt close with any resistance or not at all?

Matt_3479 · Aug 3, 2021

JBoomhauer said:
If it is a headspace issue the “right” answer is to have a gunsmith rechamber it.

The second option if headspace is slightly off is to Jam and essentially create your own wildcat. Call it a BRA+ or whatever, but it’s no longer a bra and just know what you have. The 205 primer suggestions would help if this is the route you want to go.

I personally would rechamber if the headspace is off.

Okay thank you! I appreciate everyone’s help here. Unfortunately time is limited with a baby in the house so I wanted to narrow things down as fast as possible before calling and dealing with the smith. This barrel has 2000 rounds on it and was going be for fireforming and practice while my blank gets chambered but if I’m having any headspace issues then I’ll know to deal with someone else.

I will check eveeything tn that was recommend to me and post and update.

Kinetic Moose said:
I have some friends that are switching to this because it's just no brainer consistency and accuracy. personally if barrels were in stock I would swap in a heartbeat as well.

What action are you running? I have had light primer strikes with some actions and it usually ended up being dirt somewhere, however thisguy had some issues with spring tension because he swapped triggers and the setback of the sear was different I think only .030 and it was on the ragged edge.. Might want to try a different trigger or talk to your action maker and see what clicky thingy they recommend. Joel over at terminus actions has a lot of knowledge on this that I picked up through osmosis when my buddy when through it.

This is a tt diamond and impact 737r. The previous owner said he never experience light strikes or failure to fires so I’m assuming it’s got to be something I’m doing or primer issue. Weather it’s hard primers, little my luck with bad primers ans I could just be reading into this more then I should.

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