Home Forums Hunting & Shooting Ask The Gunwriters Arisaka Action

Bullet 'Forming'

Many .30-'06 cartridges fire in rechambered but not rebored Jap 6.5 mm military rifle

Recently Enique Mahnke, a gunsmith of Cobb, Calif., set in 3 empty .30-'06 cases, one with the primer smashed very flat, and the other 2 with the primers missing and the primer pockets slightly expanded. Accompanying them was the following letter:

"Recently a man brought a Jap rifle to me and wanted me to fix it so it would not kick so much. He had been using regular .30-'06 hunting cartridges in the rifle which he said was a Jap 7.7 mm. (cal. .303) that he had rechambered himself.

"A glance at the rifle showed me that it was a 6.5 mm.(.256) and I told him he must have brought in the wrong rifle, as a .256 could not be rechambered to .30-'06 because the pilot on the reamer would not enter the barrel. He said that he had had that trouble, but had cured it by grinding down the pilot of the reamer until it would go in.

"After the rechambering was finished, he had tested out the rifle by firing 2 shots, holding the rifle in one hand on the far side of a tree, and it had almost kicked out of his hand. He then fired a few shots at a target, and went hunting with it and killed a deer, but the gun kicked so badly that he decided to bring it and have me fix it.

"I would never have believed cal. .30 bullets could be fired through a cal. .256 bore without bursting the gun, but here are the gun and empty cartridge cases to prove it.

"I am sending the rifle along to you for any tests you might care to make. If you blow the gun up, it is all right with me as it is no good the way it is. I just thought you might be interested."

This is a bit startling, in spite of the fact that the cal. 6.5 mm. Jap is an exceptionally strong rifle. It is made of extra tough material, and moreover the head of the case is unusually well enclosed, which makes for additional strength. However, few would expect it to stand the treatment described.

To find out just what a cal. .30 bullet would look like after being squeezed down by being fired through a bore only a bit over 2/3 its normal cross-sectional area, we fired a Service .30-'06 with a 172-gr. boattail bullet, a 180-gr. Remington soft-point Core-lokt, and a Remington 220-gr. Mushroom Core-lokt into a recovery box which is filled with oiled sawdust. The results are shown in the cut [photo] below.

With the 172-gr. .30 M1, the bolt handle was hard to lift, but the case extracted satisfactorily, and except for the extremely flat primer it looked normal. On the 180-gr. and the 220-gr. hunting loads, the bolt open easily, but the cartridge cases failed to extract and had to be knocked out with a ramrod.

After the test the measured headspace on this rifle was found to be 1.945", which is within tolerance for a new .30-'06. After all the beating that this rilfe had received, it remained intact, with no cracks or other damage visible.

The owner of this rifle was lucky enough to get away with a very foolish stunt without being injured. Ore firing tests were done by remote control, with recautions against injury should the rifle explode --NRA TECH STAFF