So I disassembled my Browning Abolt bolt assembly so as to safely test chambering of some reloads. Found 2 videos on youtube that explained it pretty well. Disassembly went OK. Then I went to reassemble. This is what the video showed after reassembly:
However, when screwing on the bolt handle it's possible to go around one more revolution so that the space between the bolt shroud and bolt body is less. I think you can also do the reverse - screw the bolt handle on one less revolution than is shown here.
I have tried the first and the rifle functions fine, although the bolt lift and trigger pull are a little heavier (because the firing pin spring is compressed a little more?). In fact that's how I originally assembled it. When it didn't match this picture I backed off one revolution.
Does anyone know what the spec is for bolt shroud - bolt body clearance? Is that picture correct?
for most bolt guns the front of the cocking piece hits the inside of the bolt shroud stopping the forward movement of the firing pin assembly. Assuming this, check your firing pin protrusion in the fired position.
gunmaker ------------------ James Anderson Metalsmith & Stockmaker WEB SITE
Looks like it needs one more turn in. I'll check the Browning shop manual in the morning. I think the A-Bolt FP stop is on the FP shoulder on the rear of the bolt head.
Posts: 3822 | Location: SC,USA | Registered: 07 March 2002
Gunmaker: Since the firing pin is fixed to the cocking piece screwing the bolt in and out doesn't change the firing pin protrusion. It is fixed by the distance from the bolt face to the deepest notch on the bolt (where the cocking piece ends up after you pull the trigger). Took me a while to figure that out.
Gunmaker, you are correct. The protrusion is about .045. If I screw the bolt in one more turn, it jumps to about .070. (these measurements are probably only witub .010 accuracy).
Most of the Abolt pictures show a bolt shround to bolt handle clearance that corresponds to the bolt turned in one more thread.
Service manual instructs to turn the firing pin assy into the bolt until it stops. Then turn back 1/2 to 1 turn depending on model until the sear roller lines up with the holding notch in the bolt.
Posts: 3822 | Location: SC,USA | Registered: 07 March 2002
Originally posted by sjmci: It is fixed by the distance from the bolt face to the deepest notch on the bolt
That's not how most bolt actions function. The cocking piece bottoms out in the shroud and the cocking cam has a little clearance between notch and cocking piece. This way you don't beat up your helix every time you dry fire.
gunmaker ------------------ James Anderson Metalsmith & Stockmaker WEB SITE
PM me your email and I'll send you the pics from the Browning service manual. You have to be a service center to get one. The firing pin stop is the rear of the detachable bolthead. There is a stop shoulder on the FP that stops things a hair before the cocking piece impacts the helix.
quote:
Originally posted by sjmci: Tx to all who replied.
Gunmaker: it appears my measuring device is not accurate enough for a good firing pin protrusion measurement.
Bobster: That is what I was looking for. Just curious, where does one get an Abolt service manual?
Posts: 3822 | Location: SC,USA | Registered: 07 March 2002
