Palma/TR Rifle Chamber and Barrel Twist Rate

lejarretnoir

lejarretnoir

CGN Ultra frequent flyer
Rating - 100%
136   0   0
Location
162km from Connaught
Does anyone know the the best or most popular chamber being used today for Palma and DCRA TR rifles?

Also which is the most common barrel twist for the 154gr Lapua? I hear some getting 12" twists, but that seems rather fast even for that bullet design.
 
Last edited:
I have mine chambered with a plain old Obermeyer match reamer. I don't know the dimensions of the reamer but my fired cases mic .344" This chamber passes the Bisley Rule 50 chamber test.
 
Obermeyer and 13" twist seems to be the way with Palma/DCRA. Need to also pass the Bisley Rule 50 test. I'll start there for a general purpose reamer. Is there any point in a tight bore anymore? Is .300 bore standard with reloads today and Bisley ammo? Thanks guys.
 
Last edited:
You might want to contact Barlein Barrels in regards to bore and groove diameters. IIRC they made a bunch of barrels to send to the UK. I think the barrel on my main target rifle now is a 1:12 Bartlein with .298"X.307". I can't remembers the dim. of the McClennen barrel I had on when I went to Bisley in 2007 but the Obermeyer chamber passed Rule 50 with flying colours.
 
M851, 1-12 seems to be hot setup for the long Lapua bullets. Tight bore is not recommended. As mentioned, the Obermeyer works well, as do other match reamers. The Ob. is 2 1/2 deg. per side, .3085" dia in the leade. Most match reamers and those used in BR are 1 1/2 deg per side. Ideally, a non-neck turn reamer should be used with about 2 thou. clearance.

Regards,

Peter
 
Peter, is that the M-852 reamer you're speaking of? Setup for the 168gr type bullets and used for the 154gr Lapua's? So, is it true that the 1-12" twist is optimal for the 154gr Lapua design?
 
Interesting! The Palma bullets continue to get longer. Looks like 1-12" will be the future for sure.
It seems Sierra has now come up with a new Palma 155gr bullet design.
Model #2156, 155-grain HPBT Palma

Code: 
http://accurateshooter.wordpress.com/2008/12/22/sierra-introduces-new-308-155gr-palma-bullet/

I'll be getting an Obermeyer Match GR and M-852 reamers to accommodate the different bullets, chambers.
 
PTG makes a reamer he calls a bisley 150, w/ a .341 neck. My loaded round w/ lapua brass goes .337-338, so I'm running .003-.004 clearance. I'n not sure about leade, but the throat is plenty long. 154 scenars are at the lands w/o the base of the shank anywhere near the shoulder. Broughton 1-12 5c is working nicely for me w/ both the scenars and 155.5 bergers. Of course I don't need to worry about RG ammo shooting F/TR. Then again, the NRA (UK) isn't using RG this year either.
 
You must log in or register to reply here.
Back
Top Bottom