, how long is your A4 bolt

[gigi79]

Attachment 118226

hello,

Please, how many inches is your A4 body bolt ?

Thanks

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[gigi79]

The translation should not be suitable ... Regards

[gigi79]

what is the length of your 1903 A4 bolt body?
I feel like mine lost 1mm (0.039'').

[MAC702]

Should be the same (within tolerance) as an M1903A3, perhaps any M1903?

I'll measure a few of mine and see what we get:
A4: 5.762"
A3: 5.761"
A3: 5.759"
A1: 5.768"
'03: 5.772"
'03: 5.769"

[1903Collector]

This reply does not directly answer your question But your question inspired the following reply. If my reply is missing the point of your post, please explain why you ask?

For the record, there are no differences between '03, A1, A3 and A4 bolt body lengths from any USGI manufacturer when new. They are designed and manufactured to be interchangeable. I have, however, to my surprise, noted some differences in the results in headspace gaging with different stripped bolt bodies.

The following has not been confirmed by a tolerance analysis of the bolt and receiver drawings, but were empirically determined. Yet it has raises questions in my mind.

The bolt lugs are the features that interface and sets the axial distance of the bolt face to the receiver. When short chambered a in-spec bolt will not close on a "GO" gage of cartridge. When headspace is good, wear on the back side of the bolt lugs may allow the bolt to close on a "NO GO" gage. I have seen this.

Personally, I had never considered bolt wear as a factor in any respect. But, can it be so? I am uncomfortable with the thought that '03 bolt wear is a real life factor. Otherwise why would correcting headspace always and only involve barrel replacement?

[gigi79]

Thank you very much MAC702

I see the average would be 5.765".
For me
A4: 5.740

the "no fire gauge" was closing for the bolt body A4. But with a bolt body A3, the gauge does not close: it's good.

My body bolt is HS. This is an element that is impossible to find in France. Politics never helps collectors.

Thanks again MAC702



NB : For my personal information, is there a document that specifies the position, the ranks of the snipers in a regiment, company or platoon...? At what level does he work? And specifying the complete outfit and specific equipment of the rifleman sniper M1903 a4 WW2?
If you have any elements, do not hesitate to send me a private message.

---------- Post added at 06:47 PM ---------- Previous post was at 06:39 PM ----------

At a pinch, I change the barrel to have a headspace corresponding to my bolt body but having a barrel from January or February 1943 (first block of A4) with the punch mark at 3:00, the P at 6:00 etc..., is mission impossible.

Please excuse the translation if it is not very accurate.

[1903Collector]

I used to travel to the EU monthly. I have MANY '03 bolts and could have easily brought you one. But those days are gone and regretfully cant help you now.

Please read my other reply to your post. The dim you are checking is not related to determining a good or bad bolt. Once again, I have never seen a "bad" bolt except one, just barrels with issues of chamber wear.
The feature of the bolt that can affect headspace is the back of the two lugs and their distance to the bolt face. The bolt lugs rotate against the two slightly spiral "cams" inside the receiver just behind the internal threads. The final distance of the bolt face relative to the barrel once the bolt is closed is determined by that. Note, it may be difficult to measure the distance between those features without an inspection fixture.

I dont agree that barrels and bolts have to be matched in general practice. That is an old "wives' tale" and is not consistent with the facts of the bolt/receiver/barrel chamber design. I do understand why this is often misunderstand.

However, as I mentioned, I have seen some variation bolt to bolt, but it is very rare.

[Chuckindenver]

even with the poorly done pictures, i can see your bolt is not a genuine A4 snipers bolt. why would you go through the trouble of destroying the barrel, when you can buy a replacement replica A4 bolt and have it sent to you? to add, the whole length of the bolt is not how the headspace is effected, its the face of the bolt and locking lugs, if your bolt closes on a NO GO gauge, likely this bolt has set back, damage from being opened and slammed into the ejector hard many times. if you look at the left side locking lug, the one with a notch for the ejector, it may have damage at the rear. shaped like a crescent moon.

[ssgross]

even with the poorly done pictures, i can see your bolt is not a genuine A4 snipers bolt.

That handle looks to me like the cheap CC replacement bolts with poorly done bent handle jobs that Numrich has been selling for a while.
https://www.gunpartscorp.com/products/525470b
Chuck has done 2 A4 bolts for me - shame for the rest of you he is retired now . It's good to hear from you, Chuck! I hope you are doing well.

[1903Collector]

Well stated, but I think the guy lives in France and may not be able to acquire/import a correct A4 bolt.

If those who use HS gages read the instructions they will learn that the bolt has to close freely with no load applied. Receivers and Bolts are hardened, but the gages are hardened to a higher level, and as you say slamming the bolt on a gage when the bolt does not close freely has a chance to damage the receiver or bolt. If the bolt isnt stripped as it should be it is even more prone to damage. The ejector heat treated to an even lower hardness grade, if hardened at all (Ive not seen the an Ejector Drawing) as it needs to be more ductile by design.

For the record, slamming the bolt on a gage when the bolt does not close freely will not damage or alter the gage. It is not likely to cause the gage to be out of spec. I believe they are hardened to a high level and have to be so in order to function as a gage.