1903 Bolt fit/headspace adjustment question

[bczrx]

Hi,

My Question: Is Headspace ALWAYS set with changing the barrel/chamber? Or, is there anything that can be safely done to the bolt to add about .002 of headspace to a rifle?

Situation:

I have a Remington-made 1903 from May of 1942 [NOT a 1903A3].

• The bolt [call it A] has a good fit. It doesn't close on No-Go gauge,
• closes well on Go Gauge.
• No need for Field gauge.

Long story short, I also have another bolt that I was testing to see if it fit [call it B].

• It has more resistance than optimal with 'go' gauge,
  
• and NoGo won't close more than half-way.

My 'smith said that to make [bolt B] fit, the barrel would have to have the chamber reamed about .002-003.

Yet, if I did that, then Bolt A would be over the NoGo size, and nearing/passing the Field Gauge safety specs.

This leads me to the original question above.

I was thinking [always dangerous]...

Is it possible to remove about .001-.002 from the back side of the bolt locking lugs, so that it sits that much toward the rear, and allows that increase in headspace?

or, is this a huge no-no.

Any help is appreciated. I would love to have another Remington marked bolt that fits as a backup.

thank you.

 

[entropy]

NO. HUGE NO-NO. It would create free bolt travel, something that is desirable in a semi auto, (and essential for cycling) but not in a locked action. You could either

1. Use Bolt A as is, and forget Bolt B, or
2. Ream the chamber and have Bolt A be a bit sloppy, and you'd be able to use Bolt B.

 

[boom boom]

Fire the rifle first with bolt a for accuracy check before doing anything. Military rifles are about 2-4 moa as issued. Chances are, the marginal improvement from tighter headspace by reaming for bolt b, won't be noticeable especially using battle sights of the 1903.

Probably your accurizing would do better focusing on stock and fit of fittings. For example, Loose bayonet bands from bayonet practice can have a bad effect on rifle consistency. Check trigger guard fit etc.

If you must, there are other stripped new old stock 1903 bolts that you could buy that would be cheaper than hiring reaming done. Sell the excess bolts on fleabay or gunbroker.

 

[Slamfire]

Is it possible to remove about .001-.002 from the back side of the bolt locking lugs, so that it sits that much toward the rear, and allows that increase in headspace?

The most important measurement that we do not take, is cartridge case head protrusion. If head space is excessive, then usually, so is case head protrusion. There are some gomer gunsmiths who don't use headspace gages when they cut a chamber, and the "one" I am thinking of, brags about it, and has shown no understanding of case head protrusion. Excessive case head protrusion will blow a gun to pieces, because very little of the case can stick out of the chamber.

It is well worth reading Vol IV The Machine Gun by Chinn to understand this concept.





So, whatever you do, don't grind material off the back of bolt lugs, to increase chamber headspace.

 

[Jim Watson]

Why do you want to replace a bolt that fits with one that doesn't?

If you feel you just must, have you tried chambering a real cartridge with bolt b?

 

[BBBBill]

I have a Remington-made 1903 from May of 1942 [NOT a 1903A3].

• The bolt [call it A] has a good fit. It doesn't close on No-Go gauge,
• closes well on Go Gauge.
• No need for Field gauge.

So it fits as it should. No need to monkey around with it.

I also have another bolt that I was testing to see if it fit [call it B].

• It has more resistance than optimal with 'go' gauge,
  
• and NoGo won't close more than half-way.

Forcing a bolt closed on a gauge is bad juju. Sounds like headspace is just under go.

Your question as presented suggests going from good to bad. Don't do that.

Long story short

Maybe there is more to the story, but unless the long version reveals something that none of us are understanding the answer is to leave it alone!

 

[4v50 Gary]

I'd rather face the bolt face on a lathe.

 

[shooter1niner]

Nothing wrong with having a spare bolt. I can remember my Dad having 3 or 4 03-A3's and swapping marked bolts just to see if they interchanged and fit. All four headspaced good with all bolts. Trying/buying another bolt might be an option...

I would want to make sure lugs have good bearing and if ok take the small amount you're talking about off the face using a lathe as 4v50 Gary stated.

 

[Blue68f100]

If you hand load you could size the brass on down to work with no issues. Provided the bolt will close with no round in the chamber.