Another BRA loading question.

[ARshuter]

While fire forming my cases for the BRA I have been using my 6BR load. 29.5 grains of Varget and seating my bullet .010 into the lands getting excellent accuracy. My plan once fire formed is to go to 4895. How do I want to duplicate this accuracy? I've never seated bullets in the lands before so not sure if this is what's causing the excellent targets or if it's the velocity. Any help will be appreciated. Thank you.

 

[Stan Taylor]

I feel you should start with that jam an back up in .005 increments an once you see a positive note do your changes in .002 increments.PS what bullets are you fireform with.

 

[dkhunt14]

That also depends what you are calling jam. True jam is what the gun will seat the bullet without it pushing back in case. In the lands .010 to .015 is another term. Matt

 

[ARshuter]

I feel you should start with that jam an back up in .005 increments an once you see a positive note do your changes in .002 increments.PS what bullets are you fireform with.

Sierra 107s and was planning on continuing to use them

 

[ARshuter]

That also depends what you are calling jam. True jam is what the gun will seat the bullet without it pushing back in case. In the lands .010 to .015 is another term. Matt

When I extract the loaded round it leaves marks from each land .010 long. So I guess it's in the lands .010
PS Fixed it^^

 

[Webster]

I have a 6BR and a 6BRX for GH. Light bullets. Remember that if you jam and have to extract a loaded round the bullet may stick in the bore and dump powder in the action. A real problem in the field and at the range. A week ago I jammed a 68 Berger. Extracted the case, dumped powder in the action. Removed the bullet with a cleaning rod from the front. Something happened I didn't expect. A few powder kernels stuck very hard on to the bolt camming surface. The interference was enough that I couldn't close the bolt after cleaning the action the best I could. At home I had to scrape it off with a razor blade. This ended my day at the range.

 

[swd]

Sierra 107s and was planning on continuing to use them

I've had great luck with 107's in the lands. I seat them out until the marks are square and work back from there. Most of great time they shoot well I never bother changing the seating depth. With .003" neck tension they extract without pulling a bullet.

 

[powderbrake]

"jam" is very different to different folks. If you count jam as that bullet location after closing the bolt on a bullet seated extra long, then you have to consider the amount of neck interference. .001 on the diameter vs .003 will change the "jam" length.

Some folks use a Hornady Lock& Load to locate the lands. I also use this as a check, but it does depend a little on how hard you push on the rod before you lock it down.

I am a firm believer in Alex Wheeler's method of seating a bullet and feeling the bolt close to find the lands. (With firing pin & spring removed, and with the extractor removed) This will give you a number on your calipers for the Ogive to Base length. So with this number you can then accurately seat to any number "into" or "out of" the lands.

Three tools are needed to do this. A Firing Pin removal tool, an Extractor removal tool, and a ( I think) 1/16 dia punch. The removal tools are $34 each at Sinclair, the punch is cheap. You don't necessarily need these tools , there are other ways of getting the firing pin out and the ejector out, but having them sure makes the job easy. You can safely remove the pin & ejector in 5 minutes

With these tools and this method, you can accurately assess your seating depth, AND accurately set you full length or body die to fit your chamber perfectly

 

[KenOath]

Start your powder charge test at your 10 jam, once you’ve found a powder charge that gives you the best elevation move seating depth in and out from your 10 jam in say .003 to .005 thou increments, then move in finer increments around your best seating depth of .001 to .002 thou..

 

[ARshuter]

Awesome thoughts thanks for the help guys. I'll take it from here.

 

[Pappy42]

Good thread!