Excess headspace - Win M70 30-06 pre-64

[Stammster]

Thanks for all the suggestions. I'm going to give the guys at pre-64 a call to see if they have a bolt that will work for this gun, or can modify this one.

Just to add:

I installed the bolt from my 1955 M70 (270 Win), and it seems to resolve the headspace issue. With that bolt in this 30-06, the no-go gauge would not chamber.

I measured the distance from the back of the lug of bolt to the boldface, for each bolt. The 30-06 bolt came out 0.007" shorter than the 270, thus creating the excess head space when used in this 30-06. (In addition, the 30-06 chamber appears to be 0.004" deeper vs the 270.). This is consistent with the differences of the fired brass when measured with my comparator.

The issue is likely as I suspected...once the chamber was reamed and the barrel fitted to the receiver, the assembly worker then found a suitable bolt from a pile of them that would create a finished product between the min and max allowable headspace. He then stenciled the receiver serial number into the bolt. Change the bolt, and voila...you have a high likelihood an issue like I have.

My understanding is this practice started in the financially troubling years of the later model (1960-1964) pre-64 guns. Prior to that, more exact machining and fitting tolerances were followed, so that no matter the stack up tolerances between the barrel, receiver, and bolt, the headspace was always within allowable.

 

[epoletna]

Pre-64 appears to be a small operation (no surprise). I have sent them several emails and only received one reply. In fairness, I was not always looking to purchase something. Let them know you're interested in buying a bolt (and maybe selling yours back as partial payment) and you might have more success. Good luck and keep us informed.

 

[Stammster]

Ok guys...I have an update. I was able to find a bolt for this gun. If you remember, I bought this gun used on gunbroker and it came with a mismatched serial number bolt that the seller did not disclose - resulting in excess headspace.

How do I know that it will work...well, the one I found on eBay is the exact serial number to my gun. I almost fell over when I saw it. Apparently the eBay seller bought the bolt at a gun show 5-6 years ago, and finally got around to posting it for sale.

This pre-64 Model 70 bolt and gun are finally going to be reunited!

I'm heading to the gas station to buy some lottery tickets while my luck is still good.

 

[JMW67]

Good deal even a blind hog finds an acorn ever now and then, dont know about the lotto it sounds like you may have used your luck up

 

[Dean2]

That truly is great and how lucky can you possibly get. Now you can resell your bolt and hopefully the guy that owns that rifle will spot it.

 

[epoletna]

I have heard of amazing coincidences, but that is truly one for the books!

 

[jdyoung]

Good, ......good, ....... you didn't say, but I take it you have checked the headspace with this wandering bolt in place.

 

[shortgrass]

Will still need one full turn to put the barrel engraving right, and that will show to an experienced collector.

It would take one full turn to put the extractor cut back where it is supposed to be.

 

[epoletna]

Hmmm. One full turn to make the engraving right? Doesn't sound like that is the original bolt and barrel. Just my thought.

 

[ntsqd]

That comment was made before the original bolt was found. To correct the head-space with the non-original bolt would require that the barrel be set back at least one full turn.

 

[Bob Wright]

Talk about luck. 6 digits of chance is a lottery ticket. Wow!

 

[shortgrass]

A VERY lucky find to come up with the original bolt! I made the above comment before the OP found the original bolt..