AIA #4 M10 Ejection

[Alfred]

The CMP National Match program wants issue appearing rifles, which can be worked over internally, including match grade barrels, bedding, etc. I was referring to the CMP M-1 vintage match, which had 1300 entrants last year. I suspect that this match is for original rifles.
The plunger ejector and counterbored boltface used by AIA are a good way of dealing with a rimless cartridges. The Australian .223 and 7.62x39 conversions uses boltheads altered in a similar fashion.

I'm a bit leery of the bolt heads altered by adding a ring silver soldered or brazed to the original bolt face, If a case head blew the ring would be another source of sharpnel.

Empty 7.62X39 cases eject well from my Lithgow action.

If a replacement bolt head specifically designed for the rimless cases were available it would probably sell fairly well.
There are a few machinist that provide aftermarket CNC machined accesories for SKS actions, perhaps one of these small companies would be interested in manufacturing replacement boltheads of various types.
If so some otherwise nearly unusable bolt bodies that have badly worn threads but are numbered to their receiver could be returned to good shooting condition by a new manufacture bolt head threaded a hair oversized for the purpose.

[tiriaq]

I have used a carbide tool to create a bolthead counterbored for .223. Held the bolthead in a collet, c'bore was very concentric.
I would not be surprised if there were not a market for #3, #4, even #5 sized boltheads. Just increased .005" per step.
Something to consider if converting a Lee Enfield to a rimlless round.... There is a built in gap between the barrel face and standard boltface. If the boltface is counterbored, that gap should be eliminated. You don't want any more brass hanging out in the breeze than necessary. When I was experimenting with the .223 conversion, I fitted a ratty, salvaged Sako barrel, machined it to bring it back to the bolthead. Functionned well enough as a single shot, just never picked up a really good .223 barrel to experimant further.

[Alan de Enfield]

Article on converting a No4 to .223 calibre

http://www.surplusrifle.com/shooting/no4223/index.asp

[Alfred]

I have used a carbide tool to create a bolthead counterbored for .223. Held the bolthead in a collet, c'bore was very concentric.

I'd given that some thought. The bolt heads seem to have enough meat to them to allow a shallow counterbore.

A short list of sporting cartridges I considered for a No.1 conversion.

1. .22 Savage Hi Power (shortage of proper .228 diameter barrel blanks and difficulty finding bullets)
2. 6.5X57R ( that would be a great cartridge for local game from Deer down to Turkey and smaller game with reduced loads.
3. 7X57R for much the same reasons, both are porportioned nicely for the LE actions.

4. cartridges based on the .30-30 Winchester, the .30-30 due to wide availability and inherent accuracy, the .32 Winchester Special due to it being very well suited to handloading with a wide variety of propellants including Black Powder (finding a suitable barrel blank with 1 in 16 twist won't be easy, the 7X30 Waters a very versatile chambering, 25-35 Winchester could be given just enough power with handloads for the light White Tail Deer and be used with light loads or .25 ACP in an adapter for small game.

For now I'm leaning more towards a .410 repeater, a DP mag modified to feed the shotshell, with a .22 WMR liner and spare bolt for rabbit or squirrel.