April 18th, 2017, 08:18 AM
Join Date: May 2006
Location: kerrville. texas
This may well be an effort to re-invent the wheel, but it has worked out well for me..
Sometime back, Banbam of: [Bamban's Barrel Barn fame", sent me a barrel that by accident was short one full turn, that's 1/10 of an inch short of the normal 22" barrel. In addition to that it does not have the two feed cuts in the pre-chamber, usually present on M1, M14 style barrels.
Bamban finished the proper depth of the chamber to head space at 1.634", which is what I prefer. In doing so he used a secret chamber finishing reamer..
The finished product has a lead that is off the throat erosion gauge on the short side.. M118 and M852 ammunition will not allow the bolt to close.. That's not so bad, it will later as the throat advances. Shooting hand loads anyhow, why not seat the bullet deeper in the case, setting up the bullet seater die to find a depth that leaves the bullet .015" off the lands took awhile but the effort was worth the labor. ..
As it turned, out this is the best M1A/M14 type of rifle in terms of accuracy I have owned. Maybe this has been done before on purpose, if so, it is someting to look into for the Accuracy Shooters.
The .015" bullet seating dept was required to prevent too much chamber pressure , flattenig the primers big time, even with Ted Brown's load of 39.5 Imr 4895, which is outstanding.. My usual loads had been '006" off the lands, in addition to very flat primers the impact area threatened Texas. Art