When working with custom/low clearance bolts on an M700, do you commonly relieve the center section of the bolt body (area within the receiver cutout) for additional clearance/easier running?
Gunsmithing Relieving center of M700 bolt?
- Thread starter Wannashootit
- Start date
If you mean the receiver bore, that (least in my mind) is the best course of action. The trick becomes being able to open it up in a controlled manner. For me, it was solved with a Sunnen connecting rod hone and some specialized (expensive) tooling.
At LRI we diamond hone the receiver bores. It allows us to control the ID and tailor it to whatever finish is applied later. Ceracoat is not one size fits all. The pigment saturation varies on the color of choice. Light, sandy shades require significantly more clearance than blacks or dark shades.
A guy can do this with a ream I guess, but I went this direction because of speed, flexibility, and the ability to control the dimensions and surface finish at a much better level.
FWIW the hone is around $17k for a good used one. The tooling was almost $7,500.00 and must be built case by case.
At LRI we diamond hone the receiver bores. It allows us to control the ID and tailor it to whatever finish is applied later. Ceracoat is not one size fits all. The pigment saturation varies on the color of choice. Light, sandy shades require significantly more clearance than blacks or dark shades.
A guy can do this with a ream I guess, but I went this direction because of speed, flexibility, and the ability to control the dimensions and surface finish at a much better level.
FWIW the hone is around $17k for a good used one. The tooling was almost $7,500.00 and must be built case by case.
Thanks, Chad- but no, I was referring to the bolt body itself- "customs", with a couple thou clearance in the raceway.
Perusing Y-Tube for ideas on bolt handle jigs came across a video where a respected smith (used to be on this forum) relieved the bolt body by ten thou within the area of the receiver window when the bolt is in battery- the center section of the bolt body, leaving the ends at spec.
The additional "slop" makes the bolt easier/faster to run, but when fully forward the ends of the bolt (with the tight tolerances) are fully engaged providing the precision fitment/alignment desired.
Makes sense to me, but I haven't seen discussion of anyone else doing this.
Perusing Y-Tube for ideas on bolt handle jigs came across a video where a respected smith (used to be on this forum) relieved the bolt body by ten thou within the area of the receiver window when the bolt is in battery- the center section of the bolt body, leaving the ends at spec.
The additional "slop" makes the bolt easier/faster to run, but when fully forward the ends of the bolt (with the tight tolerances) are fully engaged providing the precision fitment/alignment desired.
Makes sense to me, but I haven't seen discussion of anyone else doing this.
The Nucleus action has this "feature" where the center of the bolt body is a slightly smaller diameter than the rear of the bolt body.
The bolt when pulled to the rear flops around like a bell clapper.
Cant say whether it makes for faster bolt manipulation but I am not a fan of that feature.
The bolt when pulled to the rear flops around like a bell clapper.
Cant say whether it makes for faster bolt manipulation but I am not a fan of that feature.
I once saw a gunsmith make an adapter to put in a 5C collet that had the same threads as the bolt shroud. Then screw the bolt body onto said adapter while it was in the mill, then turn the mill on (to spin the bolt body), then buzz the whole bolt body profile down with a hand held mini belt sander running like 60 or 80 grit.
IIRC it was a tight fitting Defiance that wouldn't cycle after the 1st couple attempts at Cerakote.
IIRC it was a tight fitting Defiance that wouldn't cycle after the 1st couple attempts at Cerakote.
If you want it to run faster than you need to convert it from a two lug 90-degree throw to a 3 lug 60 degree throw.
I see it more as a "plus" on tight-tolerance bolts as minimizing the possibility of a tiny bit of grit on the bolt body binding it up, esp. for a rifle that's gonna get dirty. I've got to machine the bolt when it comes in anyway to re-solder the handle, so it's a couple more minutes on the lathe to reduce the diameter in the center.
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