Gunsmithing Stretching headspace.....

[Kells81]

My wires grandpa has had a Rem 700 in 25-06 since the late 70's or early 80's. Anyway 2 years ago me and the FIL loaded up 50 rounds for it for him. Fast forward to present time. We were looking through the brass and noticed split necks and rings around the case head area where it would separate. Since I just got done rebarrelling an M1 Garand I had the proper gauges around and started piddling. The bolt would close on the No-Go and Field. Started messing around and it took 4 layers of electrical tape stacked on the field to get some resistance on the bolt. Figured it would make a good donor action (what to build, what to build) I stopped at Academy and just picked up a new 25-06 ADL and am going to switch everything over and bed back into the wooden stock.

When we did the load work on this rifle there were none of these signs and everything seemed good to go. Any chance that the headspace is growing or is my assumption that it has been like that for a while and we missed it last go round.

 

[buffybuster]

Re: Stretching headspace.....

Headspace doesn't just "grow" by itself. Either it was long to begin with or possibly the lugs on setback with some too hot loads. An outside possibility is the barrel was loosened and not torqued properly or a thicker recoil lug installed. Is it possible a different bolt was put in?

 

[Kells81]

Re: Stretching headspace.....

Checked the bolt, and its etched to the action. Its only shot factory up to the 50 reloads which were very mild with no signs of pressure. I believe when we worked the load we could have gone up another 3-4 grains to max for the gun where we did start seeing signs. This shot the best so went with it.

 

[eddieharren]

Re: Stretching headspace.....

Possible that you set the shoulders back too far when reloading?

 

[former naval person]

Re: Stretching headspace.....

I suspect DocEd has nailed it. Perhaps the reloads were first fired in another rifle and had stretched first. Either way, the ring is due to excess headspace, probably from excess full length sizing. Cracking necks indicate work hardening. Start with new brass and size them after the first firing to fit the chamber. JMHO

 

[MikeeBooshay]

Re: Stretching headspace.....

Why don't you do this..... If you have the reamer for an .06, chamber a short ( 1 1/2" piece of scrap barrel stub ). Set the depth of the chamber in the stub such that .100 to . 250" of the case head sticks out. This is now your setback gauge.

Take that new brass that was suggested above, reload a hand full of rounds and fire them in the rifle. Take the fired brass, and measure them in the gauge with your calipers, like an OAL measurement, and record the length. This is now your fired case dimension.

Set up your reload press and die, screw the die out, several turns, your are going to size those fired cases, until, using your new gauge, you have set the shoulder back .001". Your new brass should only be used in that rifle, it should last for many firings, using the .001 setback technique.

Lots of factory chambers are too long, likely your wifes Pawpaw's was too. Doesn't hurt much except accuracy, sometimes, unless you set back the shoulder to SAAMI specs, then it overworks the brass real quick. The .06 cases don't have a real severe shoulder anyway, a little too much setback is easy to get, unless you make a little gizzy gauge.

 

[my human host]

Re: Stretching headspace.....

If it takes that much tape on a field guage to get feel there is something wrong that is not related to your handloads. Steel guages don't lie.

If you can't find any obvious signs of excessive wear than I would guess it's always been that way. At any rate, the rifle is unsafe.

 

[Kells81]

Re: Stretching headspace.....

Brass was new brass on loads given..

Talked to him and he had someone proffesionally mount the scope and lap the lugs....

Guess the action should make a nice base for another hunting stick

 

[buffybuster]

Re: Stretching headspace.....

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Poke</div><div class="ubbcode-body">Brass was new brass on loads given..

Talked to him and he had someone proffesionally mount the scope and <span style="font-weight: bold">lap the lugs</span>....

Guess the action should make a nice base for another hunting stick

</div></div>

Might have gotten just a little too aggressive. Never seen it change headspace like this, but anything is possible, especially with power tools.

 

[MikeeBooshay]

Re: Stretching headspace.....

Lapped the lugs???? Hell yes that could change the headspace!!!

 

[2156SMK]

Re: Stretching headspace.....

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">Lapped the lugs???? Hell yes that could change the headspace!!! </div></div>

I wonder if they "professionally" faced the bolt with one of those carbide facing tools too...

 

[MikeeBooshay]

Re: Stretching headspace.....

Alrighty then, think we have found the source of the new headspace. Here's your choices:

1. Set the existing barrel back a thread or two, after checking out the "lap" job. You may be blueprinting an action before you finish, with any of these options, if they futzed that up.

2. Rebarrel with a new barrel. Again, provided the action and lugs are GTG.

3. Shoot it as is, but fit new brass as described above, and watch for the same damage. I was hoping there were multiple reloads on your new brass, before the damage was seen. If not, then this is not a great option.

4. nope, no more options. Don't trade it off without fixing it either, not safe or ethical.

 

[former naval person]

Re: Stretching headspace.....

Or, you can buy .30-06 brass and full length size it with the .25-06 dies, until you get full bolt closure with a bit of feel, then fire form them to fit the longer chamber and keep them for that rifle. You are forming a "false shoulder" to headspace the cartridge on. That is probably the most economical route.

 

[2156SMK]

Re: Stretching headspace.....

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">Alrighty then, think we have found the source of the new headspace. Here's your choices:

1. Set the existing barrel back a thread or two, after checking out the "lap" job. You may be blueprinting an action before you finish, with any of these options, if they futzed that up.

2. Rebarrel with a new barrel. Again, provided the action and lugs are GTG.

3. Shoot it as is, but fit new brass as described above, and watch for the same damage. I was hoping there were multiple reloads on your new brass, before the damage was seen. If not, then this is not a great option.

4. nope, no more options. Don't trade it off without fixing it either, not safe or ethical. </div></div>

One more option is to surface grind the lug the necessary amount to bring the barrel back into headspace.
IF (BIG IF) all of the excess headspace is in the lug-receiver fit, there will be extra room for the barrel to move back.
IF the boltface was also cut, then there's a good chance that the gun would tighten up too much from moving the barrel back by thinning the lug.
There is usually about 0.015" of clearance between the back of the barrel and the front of the bolt.
Gunsmiths re-barreling guns usually set this clearance around 0.010" so there's no reason you can't take away 0.005" without a problem.

I have done barrel swaps on factory guns and they headspace is usually within a couple thousandths.
If the headspace is short, a couple turns of a reamer by hand will deepen a chamber.
If the headspace is long, grind a couple thousandths off the lug and you are back in spec.
This is not a dremel, file or milling machine job, but any machine shop will have a surface grinder if the gunsmith does not have one himself.

Don't knock it till you try it...

 

[my human host]

Re: Stretching headspace.....

If it was lapped enough to significantly alter headspace. odds are the mating surfaces on the bolt and in the action are no longer perpendicular to the boltway.

I made this mistake a time or three. I've had a hard time getting rifles with this condition to hammer consistently. I won't contradict any of the pros on this forum if they argue the point, but that's been my experience.

You might want to look at the primary extraction as well.

This is some serious nit picking on my part, but seems worth mentioning.

 

[Kells81]

Re: Stretching headspace.....

Rifle has been taken apart, and new 25-06 replaced it. Trying to figure out what I want to build out of the action. My last two were 280AI and its damn hard not to add another one to the stable.... Might ditch the bolt itself and hook it up with a 1 piece from PTG and go with another 300WM.