OzFclass

Matt P wrote:

IanP wrote:

lewis reynolds wrote:beware the tight barrel im currently running 50.2g 2209 with 180 vld for 2840. started at 51.5 and lost primers. This is a grain below my other 2 shehane barrels so start low and work your way up. regard lewis

Lewis it might be more about your chamber than a tight barrel. Do you know what length throat your chamber has?

Ian

Well all the barrels were done with the same reamer, so it's more likely to be the barrel than the chamber.
Matt P

Yes, Matt used my reamer (.189" fb) for Lewis barrels as well. With this reamer, I have had loads up to 53gns 2209 to get 2830 fps, down to what Lewis is running now, 50.2gns. The other strange thing is I have always had barrels do the usual speed up at 150 rounds, but Lewis barrel just keeps on speeding up and building more pressure, even after 500 rounds. Borescope shows no carbon build up, but his barrel and a few others I have heard of lately, just keep on speeding up?????????

Matt, Rod , yep my freebore is the same also at 0.189". Thats one unusual barrel you got there!

Another thought that could account for pressure picking up the more the rifle is fired is donut growth. If its necked up lapua brass, its possible that donuts have formed and are growing. If full length sizing the brass regularly then the growth is hastened even more. Check the cases for donuts and inside reaming is what I use to bring the case necks back to normal.

Easy to check for, just try and pass a projectile thru the neck of a fired case and if it meets with a restriction its time to ream or whatever other method you prefer to use to get rid of the donut.

I have never had donuts that raise pressure to the extent of popping primers but still may be worth checking your brass just in case. If you use Wilson dies and an arbor press you can feel the restriction when seating the bullets.

Ian

I'm not surprised that donuts would affect you with a 0.189 freebore - mine's 0.239! The 180 VLDs and 180 Sierras are the most likley to be affected. With mine, they are just clear of the donut area when the chamber is new.

Alan

Hi Rod , Sent a PM yesterday with the connection through to that yank exporter you wanted..JR.. Jeff Rogers.........................................[quote="RDavies"][quote="Matt P"][quote="IanP"][quote="lewis reynolds"]beware the tight barrel im currently running 50.2g 2209 with 180 vld for 2840. started at 51.5 and lost primers. This is a grain below my other 2 shehane barrels so start low and work your way up. regard lewis[/quote]
Lewis it might be more about your chamber than a tight barrel. Do you know what length throat your chamber has?

Ian[/quote]
Well all the barrels were done with the same reamer, so it's more likely to be the barrel than the chamber.
Matt P[/quote]
Yes, Matt used my reamer (.189" fb) for Lewis barrels as well. With this reamer, I have had loads up to 53gns 2209 to get 2830 fps, down to what Lewis is running now, 50.2gns. The other strange thing is I have always had barrels do the usual speed up at 150 rounds, but Lewis barrel just keeps on speeding up and building more pressure, even after 500 rounds. Borescope shows no carbon build up, but his barrel and a few others I have heard of lately, just keep on speeding up?????????[/quote]