Lapua brass bump question

[rmist]

I have a new 6mmBr and shot it on Saturday. After I had prepped the brass for the Redding bushing die. I was going to set it for the two thousand bump. Nothing but neck sized. How many firings does it take for the brass to need bumped?? This was the first firing on the brass. It didn't size the case at all. I've usually had some sort of sizing on other once fired lapua brass. I did measure new cases vs these once fired with a shoulder gage and they're all with in one thou after the fact of trying to bump. It's been awhile since I been doing any lapua brass, this new blue box.
Thanx again

 

[Phil]

I bump my bolt gun stuff .001.

My dies are set to bump/neck size/de-prime all at once......so it gets done every firing.

 

[Terry]

Every gun and load combination is different. If you can close the bolt on the fired brass and you like how it feels leave it alone, if not bump.

 

[dkhunt14]

If you are shooting mild loads, it may take a couple of firings before you have to bump. Matt

 

[rmist]

The bolt does fall easily with the firing pin out, so there's no issue of hard bolt. Not sure what a hot load is for this rifle yet. I've only gone up to 30.6 grs of varget. When I was shooting PPC short range those cases needed bumped every shot after fire forming. Guessing just let the rifle tell me what it likes !!
Thanx again
Rmist

 

[dkhunt14]

What weight bullets are you using? When I fireform for my Dasher I shoot 30 grains varget with a hard jam and 107 Sierras. You might not be there with the load yet. Especially if they have a good jump. I was going to post about taking the fire control out and checking them. If the bolt falls shut they don't need bumped. Matt

 

[rmist]

I am using Berger 95 gr VLD's. They were a 10 thou jam with most charges over 30 grs of varget, 450 primers. I checked the the bolt after I couldn't get any bump out of the case (with firing pin assy out of the bolt). I'll check the with the rifle first next time I shoot.
Thanx again

 

[Rtheurer]

This is not uncommon at all. For some reason folks think that there Virgin brass is going to be at its max Dimension after the first firing. I have not found this to be true. Ussualy two or three fireings for almost all my cartridges.
I had made a mistake early on when forming brass. I thought too that one time firing was all it took. Set my die to push the shoulder back .002 from that first firing. Could not for the life of me figure out why I was getting case head seperations with 4 or 5th loading. Turns out I was really creating alot of head space ( Excessive) because I was bumping brass back ( Cant remember the exact number) a ton do to the first fireforming not getting even close to the Chamber shoulder.
If for example you wanted a Custom Die made the Die Maker wants a case as an example that has been fired at least three times...
Hope my poor writing has explained what I was trying to say.. Im thinking you need to shoot it a couple more times before you set your FL die. If the Rifle Bolt closes on a fired case with no resistance... neck size only until you reach that point.

Dont do what i did... Brass is expensive nowa days.
Best of luck sir
RussT

 

[rmist]

Thank you ...That makes perfect sense and I do appreciate everything that has been said here. Never a wasted day if you learn something everyday !!
Thank you again

 

[Shynloco]

Ussualy two or three fireings for almost all my cartridges....... If for example you wanted a Custom Die made the Die Maker wants a case as an example that has been fired at least three times....... Im thinking you need to shoot it a couple more times before you set your FL die. If the Rifle Bolt closes on a fired case with no resistance... neck size only until you reach that point.

RussT

IMHO, pay attention to what Russ has written. There is no magical formula to the number of shootinsg before you bump your casings. In fact your load might determine that by injecting more pressure cause by a borderline load that might give you a tad more accuracy. Remember, each rifle is different as are the exact dimension of the chamber. Which is why I use RCBS Precision Mics to check every piece of brass I fire to see if I'll bump or just neck size that reload. And what Rus says about bolt closure is the key as well. I've removed my firing pins and extractors to find the "sweet spot" for bolt closure and then referenced that on the Precision Mic so I'll know each time where my goal for a "bump" (if needed) is. Like Rus, I hope I've explained myself clearly enough to get the message across.

Alex

 

[lpreddick]

i have over 650 firings through my 14 twist 6MM BR, all mild loads and have yet needed to bump shoulders! i chamber deprimed fired cases without the ejector and firing pin/spring and the bolt goes down nicely. my reamer is pt&g's tight neck (.2704) tight chamber. brass growth has also been nil and primer pockets are tight. i check all brass after firing. my buddies 6MM BR has a bigger chamber and he has to bump after each firing. i like tight chambers and necks.

 

[Phil]

I bump my bolt gun stuff .001.

My dies are set to bump/neck size/de-prime all at once......so it gets done every firing.

I too agree with what Russ is saying.....

I don`t bump until my brass tells me too,then i set my die up to the above specs. of .001 bump.


Phil.