06-01-2012, 09:31 PM
Prior to my range run today, my "Grendel" rifle (.264 LBC tube) shot what I considered lackluster groups--certainly not the ragged, one-hole groups that I've Satern owners post in pics here on 65G. I spent north of six Benjamins on the barrel/bolt combo straight from Les Baer, so I was disappointed that the barrel printed an average of around 1 to 1.25 MOA with factory ammo.
Before I built the gun I read (perhaps on 6mmbr.com?) that for a target gun one should opt for a clamp-on gas block rather than a set-screw block because the set screws could deform the bore. I wanted to get a clamp-on block for my .936" gas block seat, but the only one I found in steel, my preferred material, was a Model 1 Sales block. I turned up my nose at the M1S block, figuring it was inferior, and opted for a steel, low-profile block that employed set screws that I got from either Rainer or Palmetto. After all, how could relatively light pressure from a couple tiny set screws deform a heavy barrel wall?
I don't know if the set screws deformed the barrel wall, but it seems the clamp-on gas block that replaced the old set-screw block has made for an improvement in accuracy. Perhaps the much larger, heavier clamp-on block changed the barrel harmonics, but whatever the reason, factory Hornady 123 grn Amax is printing groups about half the size of groups I've shot in the past. I still need to shoot more groups in duplicate conditions to confirm, but so far my results are encouraging. Oh, and I used blue loctite under the clamp-on block during installation, whereas the old set-screw block went on sans loctite. I believe the new block is the M1S block I eschewed a year ago. I picked it up on the cheap from the ARFcom equipment exchange.
I'm curious if anyone else has experienced similar results.
Before I built the gun I read (perhaps on 6mmbr.com?) that for a target gun one should opt for a clamp-on gas block rather than a set-screw block because the set screws could deform the bore. I wanted to get a clamp-on block for my .936" gas block seat, but the only one I found in steel, my preferred material, was a Model 1 Sales block. I turned up my nose at the M1S block, figuring it was inferior, and opted for a steel, low-profile block that employed set screws that I got from either Rainer or Palmetto. After all, how could relatively light pressure from a couple tiny set screws deform a heavy barrel wall?
I don't know if the set screws deformed the barrel wall, but it seems the clamp-on gas block that replaced the old set-screw block has made for an improvement in accuracy. Perhaps the much larger, heavier clamp-on block changed the barrel harmonics, but whatever the reason, factory Hornady 123 grn Amax is printing groups about half the size of groups I've shot in the past. I still need to shoot more groups in duplicate conditions to confirm, but so far my results are encouraging. Oh, and I used blue loctite under the clamp-on block during installation, whereas the old set-screw block went on sans loctite. I believe the new block is the M1S block I eschewed a year ago. I picked it up on the cheap from the ARFcom equipment exchange.
I'm curious if anyone else has experienced similar results.