My first 6BRA arrives tomorrow

[Nature Boy]

I intend to spend as much time as I have on Friday and Saturday doing some barrel break-in and fire forming.

Here’s the question. There’s a 600 yard F Class match on Sunday. Obviously that doesn’t leave me much time to do load development.

If it were you, given the time available, would you attempt shooting it in the match? If so, how would you tackle the task?

I have Berger 105 hybrids, varget, H4895, 200 new lapua 6br cases, and 205m, rem 7 1/2 and BR4 primers

 

[Gabe22BR]

It can be done, but there won’t be time for anything else..
H4895-29-31gr in increments of .2
Hybrids .008,.12, .20 jump

 

[Alex Wheeler]

If its not a real important match I would fire form in the match. Customers have sent me pictures of 10 shot groups in the 3.5" range at 600 while forming. But it seems like during fireforming you do get some fliers.

 

[Charwell]

Around 29.5 to 30 grains 4895, br4, set your bullet at touch or slight jam be my guess cause your forming cases.edit fireform at the match

 

[R.Morehouse]

FF at the match. Built in reason if you suck....

 

[Jet]

Do what Alex said

 

[CaptainMal]

I would fireform if only because of the primers. You may need a bit of time to be sure there are no primer brand or model tendencies to "blank" as pressure goes up.

Fireforming is fun. I did it during 600 yard gong matches and laughed and laughed. I could hit 8 or so in a row and get real confident until the next one was two feet off. Best way to wake up the spotters and get you all laughing. Alex just got me laughing at the memories.

 

[mikeeg02]

My best forming load was 29.6 h4895. Which was .2 shy of the start of pressure. I would shoot a couple into a stump and make sure you dont have pressure, and then load a few with that and find seating depth. I cant remember what seating depth worked while forming, but with hybrids, my sweet spot is usually ~.012 off of what I measure using the stony point tool. One of my best loads was during fire forming. But you have to tolerate an occasional flier. With h4895 I had better luck with 450's, with varget 205m's. But I never got varget to group while fire forming like 4895 did. Afterwards I've found varget to generally be consistent. Though last weekend in my one barrel 4895 was pretty consistent with sierra's.

 

[johnnyi]

I got bored fire forming at 100 and 300. Took it to 600 for the rest. And as Alex mentioned I found the same 2-3” groups with a few fliers.

My FF load was 29.2 grains of varget with the Fed 205 primers behind a 105 VLD stuck 15k into the lands. I shot 10 shots and pull the bolt wipe and clean after each 10. With 3-4K head space crush I just did that grease process on the lugs and cocking cam... just to be sure I wasn’t running anything dry and to help maintain smooth bolt close. This above was shooting 2740-50 starting out on new Barrel by the last of the 100 pieces the velocity was nearing 2800. Usually around 2775 with some fliers touching the 2800. My barrel is 28” 4 groove .237 8 twist.

Here are a couple of the groups at 600. Red Bullseye is 2” or ear plug for reference. Call good wind and I’m sure you will be happy with the results.

 

[mikeeg02]

I shot 10 shots and pull the bolt wipe and clean after each 10. With 3-4K head space crush I just did that grease process on the lugs and cocking cam... just to be sure I wasn’t running anything dry and to help maintain smooth bolt close.

Another thing you can do is bump the new brass back with your sizing die so that it's not as hard to close.

 

[Nature Boy]

Another thing you can do is bump the new brass back with your sizing die so that it's not as hard to close.

It was my plan to run the brass through the sizing die first. I'll wait till I have the rifle in my hands first to determine what needs to be done.

Good feed back all. Looks like I'll be busy this weekend. My daughter and son want to shoot this match (it will be their first). Daughter will shoot my .308 and son will shoot his .223 bolt gun. I have a lot of ammo to load.

 

[JBT47]

It was my plan to run the brass through the sizing die first. I'll wait till I have the rifle in my hands first to determine what needs to be done.

Good feed back all. Looks like I'll be busy this weekend. My daughter and son want to shoot this match (it will be their first). Daughter will shoot my .308 and son will shoot his .223 bolt gun. I have a lot of ammo to load.

Good luck and most importantly, have fun. Let us know how it goes.

 

[X-Caveman]

Maybe someone more experienced will chime in, but I thought that the .003"-.004" crush was deliberate & desired - to help form consistent brass.

 

[Alex Wheeler]

The crush fit varies with brass lots and how far into the shoulder a guy turns. Never force the bolt on a case for any reason. A snug fit (one finger close) is desirable to get uniform blow lengths. Crush is a harsh term to describe what we're after. You may not need to do anything or you may want to bump them .001-.002" depending.

 

[johnnyi]

Yes snug fit. I just referred to crush as was the common term folks refer for fire forming. I just ocd the point of cleaning and applying new lube every ten to keep all smooth and silky. For fire forming I had most perfectly 1 finger close. But a few that were slightly tighter. I guess I’ll refer as snug fit.

 

[Nature Boy]

The crush fit varies with brass lots and how far into the shoulder a guy turns. Never force the bolt on a case for any reason. A snug fit (one finger close) is desirable to get uniform blow lengths. Crush is a harsh term to describe what we're after. You may not need to do anything or you may want to bump them .001-.002" depending.

Good info. There is a desire to get a head start on things, but It's why I didn't want to do anything to the brass until I had the rifle in my hands.

 

[Curious]

The crush fit varies with brass lots and how far into the shoulder a guy turns. Never force the bolt on a case for any reason. A snug fit (one finger close) is desirable to get uniform blow lengths. Crush is a harsh term to describe what we're after. You may not need to do anything or you may want to bump them .001-.002" depending.

An Ackley crush fit is typically 0.004" or as you have previously said use the 6BR 'go' gauge as the 'no go'.

I can't close the bolt with one finger if I do that, its usually quite a firm close. Surely anything from a one finger close to a firm close will give the same blow length?

After fire forming I find my cases are a snug fit and require pushing back 0.003" before reloading.

 

[mikeeg02]

You could set up a stump in your garage close the door and fireform some brass if the neighbors are cool
J

That's what I do during barrel break in.

 

[Alex Wheeler]

An Ackley crush fit is typically 0.004" or as you have previously said use the 6BR 'go' gauge as the 'no go'.

I can't close the bolt with one finger if I do that, its usually quite a firm close. Surely anything from a one finger close to a firm close will give the same blow length?

After fire forming I find my cases are a snug fit and require pushing back 0.003" before reloading.

You have me mistaken with some one else. I never said that. I chamber my 6BRAs .004" short on a 6br go. Thats just me, I had to standardize early on so you could use the brass in the next barrel and it would be the same. So long as its not loose in the chamber your fine, just keep lugs greased.

 

[mikeeg02]

You told me that right?

Probably. It sure makes life easier cleaning in the garage between single shots than at the range.

It's hardly noticeable outside of an insulated garage....... with the door shut lol.