Where to send a bolt for machining?
- Thread starter daroccot
- Start date
gunasauras
CGN Ultra frequent flyer
- Location
- Western Manitoba
What type of bolt? What type of rifle? What calibre? Some critical info missing I'm afraid....
gunasauras
CGN Ultra frequent flyer
- Location
- Western Manitoba
If he is talking about the Ruger 10-22, you can tighten headspace to min tolerance by grinding or machining the bolt face....I can only assume this is what he is talking about.
Bolt face to me has always meant that portion of the bolt that the rear of the case sits against.
In the case of a .22 semi-auto; to machine material from the portion of the bolt that stops the bolts forward movement would create an unsafe firearm, one that would possibly slam fire. The tolerances are correct and minimum from the factory.
Sorry for the lack of info guys, I was in a rush to get out the door...
Rifle is indeed a semi, a Remington m597 .17HMR. Currently the head space is 0.052. HMR Rim thickness is averageing 0.047, leaving up to 0.008" gap in some cases. I'm not looking to reduce this to Zero, as I have already considered the slam fire danger. I was thinking of having 2 or 3 thousands removed. In the .22lr rimfire world 0.043 is considered to be the best for accuracy where rim thicknesses are on the order of 0.041". I'm aiming to have this shooting sub MOA, currently it is about 1.2 MOA.
Most rimfire rifles are happy with a couple MOA... the only shoot cans right?
So does anyone recommend a gunsmith in Western Canada?
Thanks guys.
Rifle is indeed a semi, a Remington m597 .17HMR. Currently the head space is 0.052. HMR Rim thickness is averageing 0.047, leaving up to 0.008" gap in some cases. I'm not looking to reduce this to Zero, as I have already considered the slam fire danger. I was thinking of having 2 or 3 thousands removed. In the .22lr rimfire world 0.043 is considered to be the best for accuracy where rim thicknesses are on the order of 0.041". I'm aiming to have this shooting sub MOA, currently it is about 1.2 MOA.
LOL! Ha maybye many moons ago, I don't can't remember how much grinding/tweaking I've had to perform to get things running smoothly...guntech said:
Most rimfire rifles are happy with a couple MOA... the only shoot cans right?
So does anyone recommend a gunsmith in Western Canada?
Thanks guys.
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Sorry for the lack of info guys, I was in a rush to get out the door...
Rifle is indeed a semi, a Remington m597 .17HMR. Currently the head space is 0.052. HMR Rim thickness is averageing 0.047, leaving up to 0.008" gap in some cases. I'm not looking to reduce this to Zero, as I have already considered the slam fire danger. I was thinking of having 2 or 3 thousands removed. In the .22lr rimfire world 0.043 is considered to be the best for accuracy where rim thicknesses are on the order of 0.041". I'm aiming to have this shooting sub MOA, currently it is about 1.2 MOA.
LOL! Ha maybye many moons ago, I don't can't remember how much grinding/tweaking I've had to perform to get things running smoothly...
Most rimfire rifles are happy with a couple MOA... the only shoot cans right?
So does anyone recommend a gunsmith in Western Canada?
Thanks guys.
It is my belief the inaccuracy lies within the chamber dimensions... the throat is too large.. if the barrel was set back and re chambered using a .22 Benz chambering reamer you would see improved accuracy I am sure... I doubt you will see any change by altering the headspace by a few thou....
It's a 17HMR not .22lr. With the trigger and hammer group removed and a live or dummy round chambered with the bolt closed I can move the cartridge fore to aft up to 8 thou. Surely this is going to have an effect on accuracy.
Edit: Photo added to help clairify some things...
Edit: Photo added to help clairify some things...
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I'm not seeing the accuracy I'd like to, plus I've getting about 50% of my spent cases exhibiting "domes" on their bases. No case neck splits or OOB ignitions.
It's my belief that the large amount of space is their as a safety margin to those who don't clean their chamber as often as they should, or ever, such that when you have residue in there the rifle doesn't fire OOB...
The only problem with setting back the barrel is the way the barrel is held in to the receiver, a dovetail in the barrel and a clamp.
Don't forget that you are dealing with a blowback rifle and not a locked breach. They will show problems that aren't really problems.
Pick a Volquartsen barrel that has a tight chamber.
From what I have read, rimfire accuracy is affected by headspace, as well as by chamber details. Apparently it is not unusual for a 10/22 to respond to having the boltface trimmed back slightly, to reduce clearance between the barrel breech, and the cartridge recess in the boltface. Care would have to be used to avoid the risk of slamfires; might even be an idea to make sure that the rim thickness of the cartridges is appropriate. An out of battery discharge of a .17HMR could be nasty.
You've mentionned the measured depth of the recess in the boltface, and the observed rim thickness of the cartridges, and that it is not unusual for the caseheads to bulge back on firing. Altering the bolt to reduce tolerances might improve accuracy. You are aware of the risks involved in doing this. I would also wonder how the 597 bolt is made. Is it a MIM part? Is the bolt surface hard? Doubt that Remington would sell you another.
You've mentionned the measured depth of the recess in the boltface, and the observed rim thickness of the cartridges, and that it is not unusual for the caseheads to bulge back on firing. Altering the bolt to reduce tolerances might improve accuracy. You are aware of the risks involved in doing this. I would also wonder how the 597 bolt is made. Is it a MIM part? Is the bolt surface hard? Doubt that Remington would sell you another.
