Bolt Head Overturn
Printed From: Enfield-Rifles.com
Category: Enfields
Forum Name: Enfield Gunsmithing
Forum Description: Submit any how-to's or other gunsmithing suggestions here.
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=13018
Printed Date: March 26 2026 at 8:52pm
Software Version: Web Wiz Forums 12.07 - https://www.webwizforums.com
Topic: Bolt Head Overturn
Posted By: britrifles
Subject: Bolt Head Overturn
Date Posted: December 11 2023 at 6:21am
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While messing about with checking headspace on the T, I noticed that the bolt head overturn is somewhat excessive, I measured it at approx 30 deg. I suspect it’s been this way since the barrel had been replaced by the DCRA armorer and now has approx 1200 rounds thru it. It is certainly the bolt head that’s been on this rifle since 1965. By the book, it should be replaced. Sorting thru my spare bolt heads, I found one that appears to be an unissued spare. It’s fully blackened, including the front surface. No markings at all except for the “1” indicating it is a #1 bolt head. It measures 0.632 inches and gives about a 5 deg overturn. The current bolt head installed measures 0.631 inches, also a #1 bolt head. This will tighten up headspace a bit. But, it seems to me that the “damage is done” if there is any damage. I don’t think the loads on the bolt from firing can be taken by the threads. Screwing in the bolt head and aligning it with the body rib shows no gap between the shoulder on the bolt head and front face of the bolt body when a bit of pressure is applied pushing the bolt head back onto the bolt body. I may just go ahead and swap out the bolt head, but I wonder if that new bolt head is machined square to the axis of the bolt body like the one I have currently is… Current installed bolt head:  “New” Spare bolt head:  What do you guys think? |
Replies:
Posted By: Shamu
Date Posted: December 11 2023 at 10:28am
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You've probably tried this but . . . Unscrew the old head about 1/4 turn. Now try a "wiggle" & a "push<>pull" test. If you find any flop in either swap the heads if not keep what you have! ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: britrifles
Date Posted: December 11 2023 at 10:39am
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Yes, I did do this. While there is some movement, it does not seem any excessive or different with different bolt heads. I suspect it’s fine as is. I went ahead and assembled the new bolt head with the other spare bits I have. All of these parts were with the spares my Dad had from the 1960’s. I thought there should have been a proof mark on the bolt head, but there are no marks other than the “1”, not even a manufacturers stamp. My Fulton No. 4 looks about the same as the BSA T, and it came that way right out of Fultons also back in the 1960’s. I suspect I’m worried about nothing here… |
Posted By: Shamu
Date Posted: December 11 2023 at 11:01am
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I guessed you probably had & compared too. Maybe but at least you'll be back in spec just in case, & its minor surgery. ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |