Bolt head for Lithgow #1 rifle

[Parashooter]

The following, quoted from one of mhb's posts on another forum, may help us understand the difficulty he is having adapting to the unfamiliar SMLE -

"Some of the information in CPT Laidler's excerpt is a bit confusing: 'CHS', though obviously related to headspace, is not explained, though 'GO' and 'NO-GO' limits are clear enough; the '.050" limit' referenced is unexplained, and not self-explanatory. The permissible degree of over-rotation of the bolt head is interesting, but only useful it there are a number of candidate bolt heads to work with. . .
I was unaware of the need for the rear of the bolt head shank to contact the firing pin collar before the head is fully turned-in to the bolt body: is this critical in some way? If so, it would seem that it could be achieved (if not currently present in the assembled bolt) by increasing the firing pin protrusion until contact is achieved, and then shortening the protruding tip of the pin as necessary."

(View in context at Lithgow stock finish... - Page 3 )

[mhb]

Mike,

I have a small supply of SMLE and No.4 bolt heads, both used and nos to select from. I don't have any new Australian bolt bodies. I'm not an expert on anything. I've had much help working on Lee Enfields over the past 20+ years from folks much more knowledgeable than I. I can tell you the only thing the same about SAAMI and MoD specifications is the GO gauge at .064. I've just measured my few remaining unfitted long bolt heads and they are all .639 so they won't help get you where you want to go anyhow. A new bolt body may help if you can find and fit one. If your rifle fails the .074 No Go gauge with a .641 bolt head installed, may I suggest that there may be something else amiss with the rifle body, (receiver). Possibly the hardening in the locking recesses is worn through. What type gauges are you using to check it?

Brian

If I could acquire a new Aussie bolt body from Springfield Sporters (and they do have them), and send it to you, would you be willing to undertake to select the longest suitable bolthead (which times properly) you can find among your assortment? It is likely that such a combination would substantially improve the headspace in my rifle, and, should it prove too long, I can shorten the bolt head as needed. I did ask Springfield Sporters whether they would be willing to select and time one of their bolt heads to a new Aussie bolt body, but they have not answered my query, and initially said they do not do any gunsmithing, though I can't think why they couldn't thread a few bolt heads into a bolt body or bodies to see whether any combination of them times correctly.
In the process of working-over this rifle, I have inspected the lug seats in the receiver, and they do not appear deformed or excessively worn, so it seems that the receiver, per-se, is not the cause of the excess headspace issue.
I have Clymer headspace gauges of .064" and .067", and a suitable assortment of shim stock to be sure of the headspace measurement.

Thanks;

mhb - MIke

[mhb]

He clearly knows everything, no explanation will placate him so just sell him the bolt heads I say........

Mr. Laidler:
I am attempting to resolve a problem by determining the best possible (and achieveable) solution. Many have offered useful or at least well-intended suggestions and comments. I have tried to explain the problem accurately, to make it clear what I do and do not know, and what I feel I can or cannot do. I do not believe this to be an insoluble problem, or beyond my abilities to resolve with the assistance I've received thusfar, which, while highlighting the numerous factors to be considered, have in no way convinced me that the solution is out of reach.
If you have convincing arguments tending to show that I'm attempting the impossible, please state them, so that I can add this project to my (short) list of 'things that no fellow may do'.

mhb - MIke

[mhb]

The following, quoted from one of mhb's posts on another forum, may help us understand the difficulty he is having adapting to the unfamiliar SMLE -

"Some of the information in CPT Laidler's excerpt is a bit confusing: 'CHS', though obviously related to headspace, is not explained, though 'GO' and 'NO-GO' limits are clear enough; the '.050" limit' referenced is unexplained, and not self-explanatory. The permissible degree of over-rotation of the bolt head is interesting, but only useful it there are a number of candidate bolt heads to work with. . .
I was unaware of the need for the rear of the bolt head shank to contact the firing pin collar before the head is fully turned-in to the bolt body: is this critical in some way? If so, it would seem that it could be achieved (if not currently present in the assembled bolt) by increasing the firing pin protrusion until contact is achieved, and then shortening the protruding tip of the pin as necessary."

(View in context at Lithgow stock finish... - Page 3 )

Please read the rest of the thread, so that you may have the full context of the discussion. The excerpt was just that: I had not seen the full text, and what was included was not fully explained, nor all directly related to the headspace issue, per-se; therefore, my additional questions.

mhb - MIke

[mhb]

It's not by chance a DP rifle is it?

No. It's a John Jovino 'put-together' Aussie #1 Mk3*

mhb - Mike

[Bindi2]

You need two gauges .064 and .074. Shim stock and a guage is not accurate. You don't face the bolt body off. You may face the bolt head off. The bolt must close on .064 and not close on .074 using only gentle that is very gentle pressure. Being a JJ put together make sure it has copper blocks in the draws in place before firing. Side note to tight head space is just as damaging as to loose. Headspace allows for different rim thickness.

[Brian Dick]

I'm happy to assemble a complete bolt for you to MoD specification. That means CHS of .064 GO and .074 NO GO as Bindi states above. Nothing more, nothing less since those are the specifications I live by and the only specifications that matter. The .067 gauge is pretty much useless to me. If you're trying to get headspace down to .067, it's just a waste of a good long bolt head that someone else will probably need who's rifle is really out of specification. Unfortunately, I don't have an endless supply of them. I only have a half dozen. I'd need the complete bolt and preferably the rifle too, (at least the barreled body), in order to do the job correctly and check it with proper military gauges. I'd need all the bolt parts in order to achieve proper assembly, not just the bolt body and bolt head.

[mhb]

You need two gauges .064 and .074. Shim stock and a guage is not accurate. You don't face the bolt body off. You may face the bolt head off. The bolt must close on .064 and not close on .074 using only gentle that is very gentle pressure. Being a JJ put together make sure it has copper blocks in the draws in place before firing. Side note to tight head space is just as damaging as to loose. Headspace allows for different rim thickness.

Thanks for the input.
A properly-made headspace gauge of known dimension and steel shim stock of known and verified thickness is accurate enough in this instance.
I said nothing about facing-off the bolt body, but did mention shortening the bolt head itself (only if necessary), which appears to be an approved method of altering headspace in the SMLE.
I am aware of the need to apply little or no pressure in checking headspace, and that minimum headspace in the rifle is set so as to permit the use of cartridges with maximum permissible rim thickness or head-to-datum line case length.
The forestock itself, while new, does not have copper block inserts at the draws, but does bear evenly and properly on the action body draw surfaces, and the rifle shoots very well. I understand that coachwood compresses more readily than walnut or some other hardwoods used for rifle stocks, but that is not, as yet, an issue, and can be dealt with later as the rifle is subjected to continued use.

mhb - MIke

[mhb]

I'm happy to assemble a complete bolt for you to MoD specification. That means CHS of .064 GO and .074 NO GO as Bindi states above. Nothing more, nothing less since those are the specifications I live by and the only specifications that matter. The .067 gauge is pretty much useless to me. If you're trying to get headspace down to .067, it's just a waste of a good long bolt head that someone else will probably need who's rifle is really out of specification. Unfortunately, I don't have an endless supply of them. I only have a half dozen. I'd need the complete bolt and preferably the rifle too, (at least the barreled body), in order to do the job correctly and check it with proper military gauges. I'd need all the bolt parts in order to achieve proper assembly, not just the bolt body and bolt head.

I appreciate your offer of assistance, and may take you up on it. I am currently awaiting word from Springfield Sporters and, possibly, SARCO (or some other source) on availability of suitable parts and their ability/willingness to select and/or fit parts to achieve the necessary bolt head length and timing requirements.

mhb - MIke

[CINDERS]

In answer to your question about why the bolt head has to be in contact with the bolt body shank is that when the weapon is fired it is the bolt body and recoil lugs that take the back thrust and not the threads in the bolt body and the bolt head threads.
On the side of caution I would fit the copper thrust plates that were typical for Lithgows I have seen first hand what can happen to the draws if they are not tended to with one of my most expensive Lee's being told by the owner it shot very well I do not call a 20 MOA group at a 100m good!