30BR anybody shooting one please advice

[londonhunter]

I have a 30BR and I just cannot get 34.5 grains of H4198 and seat the bullet in.

330 Free bore Rabbinett reamer
325 bushing
Lapua 6mmBR parent case
RCBS mandrel
Neck turned to 0.009 thickness
H4198 powder
Wilson Dies

I posted it originally on the reloading section

I was advised to ask my gunsmith to ream the dies using the same reamer

Reduce charge to start from 33.0 grain

My barrel is 22 inch Lilja 3 grove 1 in 15 twist

I am at the moment fireforming with

Sierra 125 grain 30 caliber heads (cheap and cheerful)
I am now loading Berger 125 grain flat base projectile

I dropped the charges to start from 32.5 grain
shaking the powder from a 4 inch drop tube.
The buller (berger) seat OK without a problem but I am getting only 2850 fps of therabout

groups are terrible

I started to increase the charge weight by 0.2 grain and as soon as I get near 33.2 the bullet comes out as I withdrew the seat stem of my wilson die.

I am beginning to sense either this batch of lapua case have extra wall thickness

This wilson dies is very very tight in terms of tolerence

I have done something fundemnetally wrong along the way

I have come across 02 other shooter in the UK with a 30BR and either of them can get near 34 + grains of 4198 stated in the 30BR info page of this site.

Any input please ?

 

[AlNyhus]

You simply need a smaller neck bushing than your .325.

.009 + .009 + .308 (bullet dia.)= .326 neck o.d. And the Sierra 125's are barely .3080 in diameter. So, it's not hard to see where the issue is.

So, you only have .001 neck tension, if even that, after the neck springs back. As you start compressing the powder, the bullet wants to come out anyway...having virtually no neck tension just makes this situation more apparent.

A good rule of thumb for a 30BR is to use a neck bushing .004 smaller than the neck o.d. with a seated bullet.

 

[WayneShaw]

I agree with Al. Most people turn necks to .010" though, at least I did.

If you need more room, go to an "improved" version.

 

[londonhunter]

OK I will increase neck tension to 323 or smaller and come back with some results

Thank you again

 

[londonhunter]

I agree with Al. Most people turn necks to .010" though, at least I did.

If you need more room, go to an "improved" version.

If you read my reply to your previous posting I stated

Secondly I have ordered 323 bushing to give it more tension however all suppliers in the UK does not have it in stock


You must remember in the UK it not like the UK
One cannot go down to a local reloading shack or call sinclair and bingo what you want is in the post office the next morning. There is a lead time for simple stuff for up to 06 months here.

 

[AlNyhus]

You must remember in the UK it not like the UK
One cannot go down to a local reloading shack or call sinclair and bingo what you want is in the post office the next morning. There is a lead time for simple stuff for up to 06 months here.

Sinclair can drop them in the mail to you and you'll have them in 10-14 days....and at a reasonable cost. If you go that way, get a .324, .323 and .322 bushing so you'll have all the bases covered both now and for future work.

I know there are importers in the U.K. that import Berger bullets. I'd strongly suggest getting some of the Berger 125's from them. I've shot the Sierra 125's fireforming cases, etc. and it's pretty tough to get much better than .500 groups from them. Another viable bullet is the Speer TNT 125gr. Not sure if anyone over there imports the Speer line, though.

Hope this helps. -Al

 

[londonhunter]

30BR

Thanks Al for the information

I am very close to Silverstone race circuit (I dont know if you follow fomuale 1) but it is the mecca of F1. Many machnist are desperate for work at the moment and one who is my friend offers last night to turn a bushing for me on his lathe on which he makes suspension components for F1 ! Should be pretty accurate and have very tight tolerance.

Give me a few weeks will update hopefully with results.

 

[Eddie Harren]

Most bushings are made on a precision grinder. I wouldn't expect a bushing, turned on a lathe, to be anywhere near as accurate as one made on a grinder. JMHO!

 

[tiny68]

You must remember in the UK it not like the UK
One cannot go down to a local reloading shack or call sinclair and bingo what you want is in the post office the next morning. There is a lead time for simple stuff for up to 06 months here.

I have a friend in the UK that gets most of his stuff from Midway. They have distribution centers in EU I think.

http://www.midwayuk.com/