I first became aware of these was through several survival type articles. The gist is that shooting a low powered pistol cartridge in a rifle allows you to take small game such as rabbits, etc. with a much lower sound signature and obviously minimal loss of meat, .308 not being ideal for bunnies. I had first seen these made by MCA Sports (http://www.mcace.com/adapters.htm
) but had never ordered one. They have now popped up in the Sportsmans Guide (Shooting Supplies, Shooting Accessories, Rifle Chamber Insert at Sportsman's Guide) which made ordering easier and so I sent off for a .308 to .32 ACP insert.
The insert arrived and it looked like the MCA product, though there is no manufacturer’s mark. It was marked "made in USA". Brief instructions included stated that some stoning may be needed to chamber in some firearms. This was the case for mine. After some very light swipes on 220 grit sand paper, the insert chambered perfectly into my Handi-Rifle. It was then off to the range.
I fired two rounds of .308 to get a baseline for the target. I had picked up the rifle used and already scoped. It was shooting about 5" high for me at 50 yards. This was fine as I anticipated the .32 ACP would be hitting much lower.
I had with me some Fiocchi 73 gr FMJ and a few rounds of Speer Gold Dot 60 gr HP. The Fiocchi was difficult to fully seat in the adapter and I could not fully close the rifle with that round. I assume this is an OAL or case length issue. Next the Speer was tried and they worked much better, though many were a little tight.
I fired a total of seven .32 ACP rounds. Recoil was akin to an air rifle or heavy barreled .22LR. You knew you were shooting but barely. Muzzle blast was less than a standard velocity .22 and was lower than a suppressed 9mm carbine. It was quiet enough to turn heads on the line.
Accuracy was surprising. The point of impact was 11" below that of the .308 rounds with no significant change in windage. The first two rounds were a little higher than the next five, due I think to the shooter settling in and paying attention. The five shot group at 50 yards was just over an inch. If I had used a bi-pod or solid rifle rest, I feel this would have tightened up some.
The .32 ACP cut very clean holes in the target. There was no issue of keyholing at all. One interesting side note. Because there is so much free bore with the adapter and the .32 ACP round, a significant amount of unburned powder was left in the bore after each round. In general I am very satisfied with the adapter, at least in concept.