Author Topic: Source for Ishapore 2A1 Bolt heads??  (Read 1824 times)

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withergyld

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Source for Ishapore 2A1 Bolt heads??
« on: September 01, 2006, 04:14:39 PM »
I have an Ishapore 2A1 rilfe in 7.62 Nato.  I checked the headspace and it appears to be ~1.640 which is the FIELD reject maximum for 7.62 Nato.  I know that swapping to a larger bolt head can fix this problem but I do not know how to determine what size I currently have and where to order a larger one.  Any help would be appreciated.
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Thed

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Source for Ishapore 2A1 Bolt heads??
« Reply #1 on: September 05, 2006, 08:10:15 AM »
Your problem is not unusual withergyld. Most of the 2a No1MkIII Ishapore Enfields I have encountered have headspace issues which lean towards excessive. Both of mine will just barely close on a SAAMI spec .308win "No-Go" guage. But this does not concern me to much, for the underlying reason you are concerned...

The rifle is a 7.62x51mmNATO spec chamber, which has more slop than .308win.

The Enfield actions from square one are loose in design. They are notorious for having headspace issues as well as being rough on brass. Sure someone out there in forum land will say "Mine is perfect", but for the most part it is a common issue on Enfields. We judge whether headspace is safe typically from SAAMI measurement specifications. If its a 7.62x51mm Rifle... it is still yet a different set of specs. More tolerance than a .308. To complicate this further, the Enfield actions as a whole will be governed by their own "Wartime acceptance" specs. These (in .303) were much wider than SAAMI.

The base No1MkIII bolt heads were manufactured with a relative loose tolerance, erring towards long. To set headspace, the face of the bolt head was sanded/filed/stoned by the armorer to fit the rifle.

On the No.4 variants of Enfields, there are a series of different bolt head sizes. Each numberd from "0" to "3". Starting at 0 as base size, each number is a thicker bolt head by 0.003" with some mild manufacturing tolerance which may add +/- 0.0005 to 0.001". Because the headspacing a No1MkIII was a PITA... they came up with this.

My suggestion is to take your existing bolt head and measure it with a dial/digital caliper. Specifically the distance between the bolt face to where the threaded stem starts. This is going to be the determining headspace distance.

From the math you had listed, it seems like you need a bolt head which is 0.006-0.008" longer.

I would then write or call http://www.ssporters.com, and explain your problem. Tell them what you need. They may be able to send out a bolt head close to the tolerance you need. They charge $10 for the bolt head on their website.

I have had great results with this company, their prices are good and their staff is knowledgable. I have used them on a variety of Enfield restoration projects. I plan on using them again once I move into doing 7.62x54r Chamber conversions on No4MkI ruifles.

Hope this helps,

-Thed

withergyld

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Source for Ishapore 2A1 Bolt heads??
« Reply #2 on: September 05, 2006, 09:05:57 AM »
Thanks Thed,

I played a bit more with it using some shims and my actual headspace is ~1.647.  My bolt head is 0.628.  I am trying to track down a bolt head ~0.640 which would put my headspace ~1.635.  A little large for .308 specs but
ok for 7.62 Nato specs. I am working with Numrich currently.  If they do not have the proper size I will try the people you suggested next.
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withergyld

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Source for Ishapore 2A1 Bolt heads??
« Reply #3 on: September 08, 2006, 03:47:40 PM »
I got my bolt head from Numrich today.  I requested .640 and the bolt head they sent me was .643.  I had to fit it slightly before it would fit.  The bolt head was a few degrees shy of lining up properly.  I slightly stoned the face of my bolt body until the new bolt head would line up properly.  I then check the headspace with my Forrester go/no-go guages.  It will close on the go but not on the no-go.  The headspace of my rifle is now between 1.630 and 1.634.  According to my calculations based on the new and old bolt head I should be 1.632.
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