Want to check headspace on Styer conversion 303 rifle. What gauges do I need?
Posted by Trainmaster111@reddit | Firearms | View on Reddit | 6 comments
I picked up this Styer M95/51 which was converted to 303 British. I want to check the headspace as given the nature of the conversion and the age of the weapon im concerned it may be unsafe. I already had one rifle dangerously close to exploding i dont need another. I know there are GO, NO GO, and FIELD gauges but as they are $46 a piece and returns are always a bitch id like to know which are critical. Especially as i dont plan on getting gauges for all my calibers and would rather invest in 8mm mauser, 7.62x54r, or 7.62x39 gauges.
DigitalLorenz@reddit
Most rimmed cartridges, including 303 British and 7.62x54r, index on the rim of the case, not the shoulder. With rimmed cartridges even field gauges only check to see if the gun excessive space in the rim only. In my opinion buying a set of headspace gauges for rimmed cartridges is only needed for those who intend to rebarrel guns as they measure one of the lowest points of wear on most gun designs, like the barrel will be shot out before it will fail a field gauge.
Now for guns chambered in rimless and semi-rimmed cartridges a field gauge can tell you if it wear has created a situation where the chamber has excessive headspace. I would recommended skipping a no go gauge on milsurps as militaries often wanted more chamber space so the guns could operate in dirty conditions, and I have a few effectively brand new guns who will still close on no go gauges.
And excessive headspace is not a dead end if you reload as there are a few options for you to make ammo that is still safe to fire. You can bump the shoulder, which is instead of sizing the case back to factory you only kiss the shoulder to reshape it so it has the less it needs to expand when it fires. For the more extreme situations, like what is common with 303 Brit, you can neck size the case so you don't even touch the case body. Now this can require you to form cases from another longer parent cartridge or an unnecked basic brass. I do this with a few guns so they can be safely shot.
CarelessGazelle5784@reddit
Is this some kinda scout rifle build?
Trainmaster111@reddit (OP)
Dont believe so. From what ive learned thus far this is a 1951 Indonesian conversion to a Dutch Mannlicher Model 95 rebored in 303 british from 6.5x53mmR. This is the 19 inch barrel carbine which is sadly missing its muzzle brake and front sight.
Of course it will likely be used as a scout rifle. Assuming headspace is good i need to have the front of the barrel repaired and a sight installed.
Due to the Frankenstein nature however im thinking ill have to settle for a blade sight tapped or welded to the barrel as the original muzzle brakes are impossible to find.
Kromulent@reddit
A field gauge is the one that tells you if the rifle is dangerous to fire
Note that you probably need to remove the extractor first, lightly attempt to close, don't jam it in
trownweg@reddit
You don't need a 'Go' gauge unless you're barreling the rifle - you can just use a live cartridge to make sure the headspace is sufficient to chamber a round.
Between 'No-Go' and 'Field' - I'd personally go with the 'No-Go' gauge. It'll tell you if the chamber is out-of-spec for the intended cartridge. The 'Field' Gauge marks, hypothetically, the point at which the headspace is so big as to create an unsafe situation which would require the rifle to be taken out of service for repair in a combat situation. For occasional, civilian use for recreation, I'd personally make a rifle a safe queen when it fails the 'No-Go' spec.
Having said all of this, .303 is an interesting cartridge where a lot of the gauges are made to the civilian spec as opposed to the British military spec, which would cause a lot of rifles which were fielded and used successfully to fail their headspace check because the standard used by the civilian regulatory agencies is much more conservative than the standards of those who designed, implemented, and fielded the cartridge. That doesn't have to be a problem, per se, but it is something to be aware of. From my perspective, milsurp rifles are "fun" rifles and not "work" rifles and I don't mind sidelining them on a more conservative schedule than might be used in a combat situation.
Franticalmond2@reddit
If you want to be cheap, you could get some painters tape and just keep layering small discs of it onto the head of a cartridge and testing to see how much it takes for it to become difficult to close.