Excessive Headspace???

D

drover

Member
First of all let me clarify that I am not a gunsmith nor do I consider myself one, but I have worked on my own rifles for many, many years and have full understanding of the dynamics involved with them.

Now for the question - at what point do you consider headspace as excessive?
I do not have a set of headspace gauges for my Rem 700 22/250 Varminter but the issue is that it is a brass eater even with mild loads. This is an older "C" series action that has been fired less than 200 rounds and never hot-rodded, 35.5 gr of H4895 with 50 gr Nosler BT seated .005 off the lands is my preferred accuracy load.

It doesn't matter if I full length size or just neck-size, brass life is limited to about 3 reloads and I am showing enough stress at the base of the brass that I toss it. In an attempt to determine if the headspace may be a little long I used new full-length sized brass, removed the ejector from the bolt face and placed shims on the bolt face and chambered the F/L new cartridges to get a rough idea of what is going on. Using a .003 shim the cartridge will chamber, using a .004 shim I begin to feel enough resistance that I must force the bolt to start closing it, using a .005 shim I cannot close it.

I realize that this method is somewhat crude and subjective however running it to the nearest gunsmith to have it checked is not an option since he is over 200 miles away.

So do I have a "brass-eater" or is the headspace a bit excessive??

Be gentle, but give me your honest opinion or if more info is needed let me know.

p.s. - The rifle is an honest 1/2" rifle day in and day out so I may end up just living with it irregardless of the issue.

I have also posted this in the Gunsmith Forum.

drover
 
You're wasting time if you don't check with headspace gauges. Using brass won't work because it is all over the place. If you use sized brass you could be even further off.
Butch
 
If this is a factory barrel and neck sized cases are only lasting 3 or so reloadings there's something wrong with the chamber. Many years ago when I was young(er) and innocent I bought a Ruger 77V in .22-250. If I FL sized cases they would last 2 or 3 firings before the head separations began. If I NS the cases I could get reasonable case life, maybe 7 or 8 firings. The problem was that the chamber was WAY too large in diameter.

Most new unfired brass is minimum minus so using it as a basis for measuring headspace likely won't prove or show what the problem is, but if a new unfired case with a 0.004" shim gives resistance on closing the bolt excessive headspace is likely not the problem.

If you have a good micrometer or dial caliper measure diameters on a fired case at about 0.2" above the base of the case, at the shoulder, and case neck, and compare the measurements to the dimensions of a .22-250 case in a loading manual that shows those dimensions. You'll likely find that your fired cases are considerably larger than the dimensions shown in the manual.
 
Thanks for the replies. A little futher info -

The barrel is factory and unmolested.

I have my dies set so that they just bump the shoulder and I cannot feel any discernable difference between new/unfired brass and stuff that I have run through my F/L die.

There is no difference in brass life whether I F/L size or Neck size.

I suspect that you may be right about the oversize chamber. I do have a good micrometer and also a good set of digital calipers, I will run some checks against the loading manual dimensions.

Thanks again for the replies, keep them coming - it is a sorry day when I don't learn something.

drover
 
The least expensive solution would be a bushing FL or NS die. If the only part of the case that's way oversized is the neck I'd order a bushing FL die, set it to just bump the shoulders, and order a neck bushing that's 0.002+ under the neck diameter of a a loaded round (over the bullet's shank). That might help a little.

The real solution is a new barrel, but if you can get better case life with a bushing die, and the rifle shoots 1/2 MOA live with it until the barrel is shot out, then get the rifle rebarreled. The road to the downfall of another young man.... ;)
 
If your chamber is truly oversize, you are in essence shooting a wildcat round. I would think a Lee collet die would do you a fine job. If you are not hot rodding your loads you should be able to get 5-10 reloads out of them. Might have to anneal the necks once.

Donald
 
OK, another opinion! :)

I check headspace this way all the time. It's perfectly fine. Your method of determining the clearance ON YOUR BRASS is not only adequate, AND the only way to actually check clearance on your cases.......but it's accurate enough to chamber off of. IMO your chamber is fine, well within tolerance. I'm betting that it won't accept a typical no-go gauge based on your measurement. And if it does, join the club. Factory rifles vary by .006 in length and .004 in diameter just IME. And I'm not all that experienced.....

Headspace gauges are handy but certainly no magic dealio.... and they vary too. The one place where they ROCK is for the gunsmith who does a lot of factory chambering. Especially on factory actions with their tapered lugs.


I recently ordered a custom reamer and a headspace gauge FROM THE SAME COMPANY, they made both parts. And the headspace gauge was (is) 18 thou longer than the fit I want on the brass. I chamber with the gauge and feeler gages, when it won't let go of an .018 feeler I check final fit using cases. That said, 22-250's ARE brass eaters. I'm a fitted die freak, I have dies made for specific chambers, and I've had two chamberings that I've never been able to get satisfaction with..... the 22-250 and the .243AI.

If you DO decide it's not worth the money and buy a barrel consider a better chambering than the 22-250....The 22BR will eat the 250 for for lunch and solve all the problems inherent to the 250 case. And the 22X47L will do things the 22-250 can only dream of.

IMO you'll be best served keeping loads light and necksize only BUT...... you said you've tried this and are still only getting 3 reloads. My guess is that you're not really neck-sizing ONLY but that you're just backing off the FL die and using it to size only the neck??? Have you got an actual ns only die or collet die? You CANNOT "neck size only" with a standard die.....Altho with a 22-250 if you only size half of the neck you might get away with it since the body is so radically tapered. If you really DO necksize only the brass should last until the neck itself splits as there's simply no mechanism for case failure. But your cases will get TIGHT! Keep your lugs greased.

opinionsby




al;
 
Al,

Thanks for the inputs - there is an even longer thread on this post running on the Gusmith Forum, I posted this over there in response to some inputs and thought I should post it here also in case anyone here had any more thoughts on it;

Gentlemen,

Thank each and everyone for their responses.

I have used the bent wire trick and I can feel the crack inside the case at the same place the shiny spot is. Using the magnifer on my inspection lamp (I am unsure of the magnification but it is a typical mounted desk lamp with a magnifer and a built in light) I can see the impending separtion on the case, at the shiny ring just forward of the web area. I have tried going beyond 3 to 4 firings with a few of the cases and invariably I have had head separation.

I am using Lee Collet dies which are set to resize the top 2/3 of the neck, I have determined this by smoking the case neck and setting the collet die so that it is only resizing the top 2/3 of the neck, it is definetly not hitting the shoulder.

I did do some more measurements of the fired cases, in comparing the fired cases to new WW brass, the web area is .002 to .003 larger in diameter. Measuring the impending failure area (shiny ring above the web) it measures .002 larger.

I did try the tape trick but the bolt will not close on a piece of electrical tape, I measured the tape thickness afterwards and it was .007, so since I cannot close on a .005 piece of shim stock that was no surprise. As mentioned a piece of .004 shim stock will require forcing the bolt over while a piece of .003 gives just a touch of resistance, just enough to know that I am chambering a cartridge.

pbike - thanks for the pictures and very clear instructions on how to build the gauge, building one of these just went to the head of my to-do list.

My loading procedure has been to prep the brass by an inital neck sizing, check for trim length and then load it. At the time that I can see failure traces beginning to occur the brass is starting to give a slight resistance to chambering.

Failures do not occur like clockwork at 3 firings, in a few instances I have had 5 firings before failure but more often than not at 3 is when the cases are starting to show external signs of separtation. In some instances at 3 loadings the stress cracks are visible with the naked eye using a bright light or in sunlight.

More thoughts - After looking at all of the answers and suggestions and with the measurements I have taken I do not think I have a headspace issue but the next time I am in the city I will find a smith and have it checked. I am beginning to wonder if the chamber is oversized after taking the measurements of the body. In the few instances of brass life that lasted long enough to require F/L resizing (usually after 3 firings) then failure occured within the next 1 or 2 firings.

I do not have a shoulder bump die but have set up my F/l die so that I am just bumping the shoulder, so perhaps I am fooling myself there and instead of just bumping it I am forcing it back further than I believe. To be sure of this I intend to build a gauge as illustrated by pbike.

My next step is to take 20 pieces of new WW brass, neck size them, check them for trim length, number them 1 through 20. I will fire them and only necksize them until such time as they give too much resistance when chambering, at that point I will F/L resize them by doing a minimal shoulder bump on them. I will keep a log of each piece of brass, by number, and the times necksized and F/L resized and number of times each before impending failure.

I have been reloading for over 45 years, not as a caual reloader but as an active high-power competitor and varmint shooter on average I go through 2000 to 3000 centerfire rounds per year. I suppose the fact that I have never had something like this occur before is why I am so frustrated with it. Although I have owned this rifle for a long time this is my first real go-round with 22/250 loading and I know they have the reputation of being hard on brass but I have to believe that it is something more than that in this case.

After all of the ideas that have been posted I am to the point where it appears as though it is something that I am doing that is causing the problem.

Thanks again and any more thoughts pop up please post them.

drover
 
Looks like Boyd gotcha' covered :) I'm surprised that you were getting these results with only from .003 to .004 of clearance but hey..... learn something every day. Maybe the firing pin was driving another couple thou.....

ANYway, I completely agree with Boyd's fix. And your rifle should shoot even better now too.

Awesome


al
 
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