how do you enlarge the headspace on a 1903?

[Daskraut]

I just re-barreled my 1903 and the gunsmith said it is super tight, and only use match grade rounds. Well even my CMP ammo will not let the bolt close!, I tried 5 different types of ammo, no-go. So how do I increase the head space?. I have heard of reaming the barrel. Can you take a little off the bolt face?.

[Scorch]

You will need a barrel vise, an action wrench, a reamer and a lathe (or a very steady hand). I have touched up chambers by hand if they are very very close.

[DnPRK]

Get a pull through reamer from Brownells.com and a set of headspace gages. Use a 50/50 mix of lard and transmission fluid for cutting lube. Turn the reamer by hand 2 revolutions and withdraw to clear chips and reapply the lard/transmission fluid mixture. Clean the chamber and check with the GO gage often (you have to disassemble the bolt first). Repeat the hand ream/GO gage check as necessary until the bolt handle just barely drops (don't force it). You'll end up with a perfect chamber.

[Daskraut]

DnPRK, do you have a .30-06 reamer?, I am close to L.A.

[Harry Bonar]

Sir:
DO NOT "grind" anything on the bolt! You can get a reamer from Brownells and just remove the bolt and use an extension on the reamer and with plenty of oil just barely remove a little from the chamber and try a new factory loaded round - you should get bolt closure and have some feel of the bolt-face touching the case.
Harry B.
P.S. It will just take a turn or two lightly on that reamer!

[James K]

Hi, Scorch,

It sounds like you are suggesting he remove the barrel, and I certainly wouldn't suggest that. You always do the final finish reaming with the barrel in place on the receiver so you can headspace with the bolt, as DnPRK and Harry say. But, with due respect guys, I strongly recommend using a GO gauge, not a cartridge, and good cutting oil, not a home-brew mixture.

(See, now I made three guys mad at me! I don't get a chance to do that very often.)

All of which sounds fine, but since you had a gunsmith do the rebarrelling, why not have him finish the job? Certainly an implied warranty is that you can use the rifle, and you can't, so he should correct it. IMHO, that "tight chamber for accuracy" is very often BS by a gunsmith who either doesn't know how to finish ream the chamber or is too cheap to buy the proper gauges.

Jim

[Harry Bonar]

Sir:
I can agree in total with Jim.
Harry B.

[T. O'Heir]

"...and try a new factory loaded round..." That'll tell you absolutely nothing about the headspace. Headspace has nothing whatever to do with the cartridge. Factory or otherwise. It's a rifle manufacturing tolerance that allows ammo from different makers to be used in every rifle chambered in a given cartridge.
Like Jim says, take it back. You can rent the finishing reamer yourself, if need be, but the rifle is useless the way it is now.

[tINY]

I'd be less than pleased if I paid good money to have a rifle re-barreled in a common caliber and couldn't use factory ammo...

This "gunsmith" needs to finish the job - else find someone else to do it and use him for all you future work.



-tINY

[Harry Bonar]

Sir:
Headspace has everythig to do with the cartridge, and its fit in the chamber. Yes, there is some variation in case dimensions (new factory ammo) but when using gauges (which, I agree should be used) you can, with certain brands of ammo end up with .006 headspace!
Yes, I use gauges - but I also on new factory cartridges like to "feel" the bolt close.
Oh! Yea! the case has everythibg to do with headspace - particularly with handloads and sizing habits. If you size your case according to die mfg. advice you'll end up with incipient case head separation - think about it.
Harry B.

[Huntzalittle]

Sir
Would you kindly expand on this statement?
""If you size your case according to die mfg. advice you'll end up with incipient case head separation - think about it. Harry B.""
I read your comments with great respect and I have thought about it, but not sure I come to your point. Obviously, I would benefit from your wisdom. (PM me if you feel I am "Hi-jacking" the thread)
Thank You!
Huntzalittle

[Harry Bonar]

Sir:
Present die manufacturers tell you to raise the ram (with proper shell holder in) and then screw the die down on the shell holder. This, in their minds restores the case to factory dimensions. That's true, with most dies.
Here's what happens:
As cases are fired there is a very slight "set-back" if most all locking lugs (most factory rifles only have one lug touching anyway and the rifle with wear will have a compression of the new lugs of about .002 to .003.)
Now, your case, will have a manufacturing tolerance - sometimes a considerable tolerance and the primer goes forward pushing the round several thousandths up to the datum line in the shoulder of the chamber. Then the rifle fires - the case walls grab the sides of the chamber and stay there while the case head goes back to the bolt-face and you stretch the case by thar amount. After several firings and re-sizing like most manuals say to you have the start of incipient case head separation (consult the "A-Square rifle and loading manual - any shot you want). As you size a fired case you want to feel the bolt actually contact the head of the case to prevent this - this is little known and is very dangerous in loading belted magnum cases - the most dangerous case design.
Harry B.

[Huntzalittle]

Again, you bring excellent information and experience to the discussion!

[James K]

Here is something I wrote a while back. It is long, but may help.

To begin with, the "head" of a cartridge is its base or back end. That's why the markings on the back of the cartridge case are called the "headstamp".

So, headspace is simply the space for the "head" of the cartridge. In a rimmed cartridge, this is obvious, but for all cartridges, it really is a measurement of the room for a cartridge from the bolt face to whatever stops and supports it in the chamber. For rimmed cartridges, that is the front of the rim; for belted cartridges, it is the front of the belt. For cartridges like the .308, measurement is taken from a specified point on the shoulder; for a cartridge like the .45 ACP, the measurement is from a sharp shoulder which abuts the case mouth. So we say that a .308 headspaces on its shoulder, and that a .45 headspaces on its case mouth. For our purpose here, we will assume that the gun is a rifle in .308 Winchester, but we need to know that headspace is a factor in pistols and revolvers as well.

Some headspace is absolutely necessary; if no tolerance is allowed, operation of the rifle may be difficult or impossible. But while there is a correct range, headspace can be wrong in either direction. If there is insufficient headspace, a cartridge will either be difficult to chamber or will not chamber at all. In combat, this could spell disaster more certainly than excessive headspace.

What problems can result from excessive headspace? The answer is in what happens when a rifle cartridge is fired. The front of the cartridge case is made thin, because it needs to expand to seal the chamber and prevent high pressure gas from coming backward. But that thinness means that under pressure the case will grip the chamber walls very tightly. The rear of the case, being thicker, will not expand, and the pressure will push it backward as far as it can until the breechblock or bolt stops it. The case will stretch. It is nearly impossible to prevent some case stretching; if the gun is to operate normally, there must be some play between the bolt and its locking mechanism. But if the stretching is such that it exceeds the elastic limits of the case material, the case will tear apart. At best, this will leave the front part of the case in the chamber and hang up the gun. At worst, high-pressure gas will be released into the system and possibly damage the gun or injure the shooter.

Some folks confuse excess headspace with an oversize chamber, and think that excess headspace can be handled by reloading without full length resizing of cases. That is true if the case has simply expanded into an overlarge chamber, as it will do if the case head is held by the extractor or the case is rimmed. Even if headspace is excessive, and the breechblock can actually back up, neck sizing can delay the inevitable, but not prevent it. The condition will worsen with firing until no care in reloading can compensate, the case head will protrude too far from the chamber, and the case will bulge and blow out, with the pressure release wrecking the rifle and possibly injuring the shooter. No one should be deluded into the belief that excess headspace is not dangerous, or that reloading techniques will correct it.

Why are measurements needed? Why are two measurements necessary? Why not make every chamber of every gun to the exact dimensions required?

The answer involves the nature of machine work. Chambers are reamed with a tool called (surprise!) a reamer. If only one rifle were to be made, it would be possible to make a reamer to the exact dimensions and it would cut an exact chamber. But in mass production, it doesn't work that way. The designer of a cartridge specifies certain tolerances, based on his knowledge and, to some extent, the anticipated use. When a reamer is made to cut chambers for that cartridge, the reamer is made to the outside tolerance, or the largest allowable size. As chambers are cut, the reamer wears, and when it becomes dull, it is sharpened. This continues until the chamber is at the smallest allowable point, when the reamer is discarded and a new one used.

This system introduces one element of variation in cartridge chambering. The other is simple wear. When a rifle fires, the pressure generated inside the cartridge case pushes back the case, which then pushes back the bolt, which then pushes on the locking seats in the receiver. After a while, the bolt lugs and the receiver wear enough from this pressure, combined with the friction of normal operation, that the bolt can move more than desirable under pressure, and we say that headspace has become excessive.

Now, remember that reamer that was used to cut chambers? Well, it is not the only reamer involved. Reamers also cut the chambers on tools used to manufacture ammunition, and they are used and sharpened the same way, so the size of the ammunition can vary. Reloaders use sizing dies that are also made by reamers, and those reamers are made and used the same way. In factory production ammunition is made to tolerances, so some cartridges may be said to be "long" and others "short" even in the same batch.

Now, when a rifle barrel is made it is either not chambered at all, or given a "short" chamber. Unchambered barrels are used by gunsmiths to build rifles for custom cartridges. Short chambered barrels are used where the final caliber is known, but it is desirable to adjust headspace after installation of the barrel and selection of a bolt. Two gauges (or gages) are used at the factory and by gunsmiths to ensure that the chamber and bolt are within specifications for the cartridge. These are called the "GO" and "NO-GO" gauges. Their use must be understood in terms of the tolerances of the cartridges that the rifle will use.

The GO gauge ensures that the rifle will close and operate with the longest cartridge that is within tolerances for the ammunition. The NO-GO gauge ensures that the shortest cartridge that is within tolerances will not be allowed to stretch far enough to exceed the elastic limits of the case material.

But we mentioned that normal use of the rifle will cause changes in the dimensions of the locking system and the locking seat(s) in the receiver. That fact led to the development of a simple "one gauge" test to ensure that the rifle has not become dangerous. This test is by use of a FIELD gauge. A rifle that accepts a FIELD gauge may be nearing, at, or past the danger point; the only way to know which is by knowledge of that rifle, or by the "feel" of the gauge. At best, failure of the FIELD gauge test delivers a warning, like the wear ridges on tires. At worst, it signals certain danger. Even a rifle that fails the FIELD gauge test may function normally with cartridges at the long end of the cartridge tolerance, yet be dangerous with cartridges at the short end.

The term "FIELD gauge" should not be taken to mean "the field" in a military sense. No one calls "time out" in battle to check soldiers' rifles with a FIELD gauge. In this sense, FIELD simply means any place outside the factory, such as a depot or an arms room.

Another point of concern is how long a normal rifle will last, in terms of rounds fired, before headspace needs to be checked. For most shooters, the answer is, "Don't worry about it." The fact is that most rifle owners will never live long enough to see their rifles develop excess headspace. But in military service, especially in "familiarization" firing, rifles wear out rapidly, and headspace checks are routinely carried out. Match shooters too, who often fire tens of thousands of rounds a year, will check headspace every few months.

In most cases, headspace should be checked every five thousand rounds, just to be on the safe side. But the reality is that barrels will usually wear out before headspace becomes a problem, and many match rifles have had several barrel replacements with the same receiver and bolt. Since a new barrel will be final chambered on the rifle, the headspace will always be reset at the time of barrel replacement. If bolt or receiver wear makes it impossible to obtain proper headspace, the worn part is scrapped.

Jim

[intruder]

I agree with tiny. You should take it back to the gunsmith He didn't perform the work to acceptable standards. You should be able to close bolt on any factory round or reload. He did not headspace the barrel properly. Why should you have the expense of buying a reamer and headspsce gauge to do one rifle when these items should be part of every gunsmith's tools.

[Daskraut]

UPDATE!
Being a newbie dingbat type, I forgot to feed the rounds being checked from the bottom, now after fixing the H.U.A. factor, I fed a new CMP round into the chamber and it closed, but it was snug. I then fed a ty milsurp round in and it also closed...tightly . Is zero space/clearance between the lugs when the round is chambered acceptable?. There is .0000 space period, plus a very light load to shut the bolt (one finger will do it). I was wondering if I can use an old casing and lap the chamber with a little fine lapping compound?, . If this is really incorrect, be gentle!. I often over simplify repairs. Anyone live in the los angeles area have a .30-06 reamer and some time?.

[tINY]

It's fine, shoot it.

Zero headspace or a slight compression of the brass is not a problem in a bolt-action rifle. Where you can run into problems is lack of free-bore.

If you don't trust this gunsmith, take the rifle to another one and have it checked out.

If you are hell-bent on messing with a messing with a rifle's chamber, get a used savage or a surpluss Yugo mauser.....





-tINY

[Harry Bonar]

Sir:
Tiny is right - it sounds as if the headspace is perfect!
You might have been droping a cartridge in the rifle without letting it feed under the extractor. Your gun sounds fine.
Harry B.

[Daskraut]

I went ahead and made a simple lapping tool out of an old case and just touched the seat area of the barrel, I think there was only a high spot. After cleaning, it feels really good now.

[tINY]

Are you ever gonna shoot the thing, or just fondle it in the garage?

Maybe you should get some jewlers rouge and an eraser and jewel the bolt. Or at least buff the stock with floor wax.



-tINY

[Daskraut]

LOL!!!!. Ok funnyboy, first off, since I am an apartment dweller, the kitchen is my workshop (when the wife is asleep) and I will break in the barrel saturday at the range. I am going to do the 1 shot, clean, shoot again, clean again 10X, then shoot 2 rounds before cleaning 5X till I have shot 40 rounds. does that sound correct or am I being a poindexter??. It is what my gunsmith reccomended. how say you?

[Harry Bonar]

Sir:
Sounds like you're getting along fine!
I know how things are "when your wife isn't home" stuff! Be careful or you'll be in serious trouble! Wives are like nuclear weapons - they can go off!
Harry B.

[Eghad]

So what is the truth about Barrel Break in? I have never broken in a barrel. I usually clean and inspect new firearms before they go to the range. I fire 20-40 rounds on a rifle then a quick cleaning of the barrel at the range and a more detailed cleaning at home. I have never used any of that lapping paste on a barrel.

Is barrel break in another urban legend?

[tINY]

For most people, barrel "break in" is a waste of time - You run a risk of dammaging the barrel by cleaning it and it doesn't do anything for practical accuracy or barrel life.

In fact, the slight changes that happen in the first couple of hundred rounds of non-hand-lapped barrels actually will take longer and the eventual accuracy will take longer to settle out.

In the Kraut's case, though, that regiment sounds like it's just right.




-tINY

[Harry Bonar]

Tiny:
I agree totally with you about bbl. break-in. I usually clean after about 20 rounds - I use Douglas bbls. and they're about the smoothest made.
Harry B.