Kirk
07-23-2010, 08:28
A friend has a Columbian M98 Mauser chambered in .30-06 that had been customized. The receiver is marked .30 so the barrel is apparently Columbian issue. The bolt would not close on any .30-06 round nor would it close on a Go headspace gauge. With either, the bolt would close no more than half way, similar to how a bolt, in a rifle with correct headspace, closes on a No Go gauge.
We deduced the barrel was set back 1 thread and rough reamed but not finish reamed. A second friend had a through the bore reamer and volunteered to finish ream the chamber. The reamer is attached to a rod. The rod extends through the muzzle where it is turned by hand. The stripped bolt is inserted from the rear and the merest finger pressure applied on the bolt handle. No real pressure is applied, just enough to you can feel the reamer working & lower the handle as cutting progresses.
52295231523352325230
At first, all the cutting was in the last .7 inch of the body; almost none on the shoulder. This is not what we expected. After numerous turns of the handle, a considerable amount of shavings appeared on the reamer. Finally, the reamer made contact with the shoulder and from then on, just a few more turns were needed. One complete turn lowered the bolt handle about 20 degrees. When the bolt handle touched the receiver, we stopped reaming, cleaned the chamber again & checked headspace. The bolt now closed OK on a Go gauge.
The next step was test firing. The rifle was affixed to a bench & fired with a lanyard several times. All the cases looked normal so the job was pronounced a success.
We deduced the barrel was set back 1 thread and rough reamed but not finish reamed. A second friend had a through the bore reamer and volunteered to finish ream the chamber. The reamer is attached to a rod. The rod extends through the muzzle where it is turned by hand. The stripped bolt is inserted from the rear and the merest finger pressure applied on the bolt handle. No real pressure is applied, just enough to you can feel the reamer working & lower the handle as cutting progresses.
52295231523352325230
At first, all the cutting was in the last .7 inch of the body; almost none on the shoulder. This is not what we expected. After numerous turns of the handle, a considerable amount of shavings appeared on the reamer. Finally, the reamer made contact with the shoulder and from then on, just a few more turns were needed. One complete turn lowered the bolt handle about 20 degrees. When the bolt handle touched the receiver, we stopped reaming, cleaned the chamber again & checked headspace. The bolt now closed OK on a Go gauge.
The next step was test firing. The rifle was affixed to a bench & fired with a lanyard several times. All the cases looked normal so the job was pronounced a success.