Home Forums Reloading Big Game Rifles Excessive Headspace?

I have a 6mm Rem built on a Mauser 98. It's a beautiful rifle that was my grandfather's so i don't now much about its usage, other than it was built 50+ years ago.

I have reloaded several loads with various powders (not close to max), bullets and seating depths only to get 3-4" groups and sometimes they open up to 6". Primers are slightly flattened, lots of soot on the neck and poor groups. Also, I have had some cases of once fired brass crack about 3/16" above the web. Is this an indication of a headspace issue? If so, what causes it and how easily is this situation corrected? thanks.

Yes, most likely headspace. You should sell the rifle to me and I'll take care of it for you. Seriously though, take it to a GOOD gunsmith, have the headspace checked. If it's within specs, then you're setting your shoulder too far back when re-sizing your cases. Keep us updated on how it turns out.
Selmer

You have some control of headspace in reloading. As a matter of fact, you can create an excess headspace condition by sizing your brass too much and setting the shoulder back too far.

The best thing to do is have a qualified gunsmith check your headspace. If excessive you can talk to him about correcting, which involves taking one thread off the barrel, rechambering and reassembling. You must also correct the barrel bedding if it's not a floated barrel. If it's not excessive, then size the brass properly to fit the chamber and don't set the shoulders back so far.

You can get by without the machining in another way if it is a rifle problem. You can form new brass with cheap bullets fired at moderate pressures to fit your chamber. You'd have to do this with every brand new lot of brass. Load them up so the bullets engrave in the lands and fire away. That will stretch your brass to fill the chamber. Then, load as normal except when you resize the brass either neck size only until you get chambering resistance at which time you can partially full size the brass setting the shoulders back no more than .002" by adjusting your sizing die.

Are you sure it is a 6 MM Rem?

Case heads seperating on the first firing doesn't sound right, even with excessive head space.

The soot on the neck is being caused by the neck not sealing in the chamber and letting gas blow by onto the brass.

Flattened primers? That might or might not be from excessive pressure. The neck not sealing and letting gas blow by is not indicative of high pressures. High pressures should seal the neck-shoulder area and prevent this.

Check and make sure you are using the correct powder for the bullets and loads you are using. Do not use a reduced load of a slow powder.

It might still be a good idea to let a gunsmith check it and make sure you are using the correct ammunition, and that the headspace is in the correct range.

Let us know what you find out.

Selmer says to take it to a good gunsmith. I have read this many times by other people. If it were my rifle, I do not know where in Georgia I would take it and trust what the gunsmith said he found.

One reason is that very few gunsmiths, unless they build custom rifles and install barrels would not have a complete set of head space gauges.

Are you sure it is a 6 MM Rem?

Case heads seperating on the first firing doesn't sound right, even with excessive head space.

The soot on the neck is being caused by the neck not sealing in the chamber and letting gas blow by onto the brass.

Flattened primers? That might or might not be from excessive pressure. The neck not sealing and letting gas blow by is not indicative of high pressures. High pressures should seal the neck-shoulder area and prevent this.

Check and make sure you are using the correct powder for the bullets and loads you are using. Do not use a reduced load of a slow powder.

It might still be a good idea to let a gunsmith check it and make sure you are using the correct ammunition, and that the headspace is in the correct range.

Let us know what you find out.

Selmer says to take it to a good gunsmith. I have read this many times by other people. If it were my rifle, I do not know where in Georgia I would take it and trust what the gunsmith said he found.

One reason is that very few gunsmiths, unless they build custom rifles and install barrels would not have a complete set of head space gauges.

Yes, I'm sure its a 6mm Rem, and as I said, the brass was once fired brass. It doesn't separate all cases shot, but it has +/-5 times.
My loads are as follows: Once fired Rem Brass, 42gr IMR4350, 100gr SPBT, Fed GM210M, OAL: 2.830.
Most cases shot out of this rifle have shown flattened primers, regardless of case, charge or bullet used. I use a Nosler Reloading Guide.

Thanks for your help.

Have your headspace checked. I presently own a "custom" mauser in 7mm-08 that I know has excess headspace. Besides cases cracking on the second firing with moderate loads it also exhibits flattened primers. By necking cases up to 35 cal then necking them back down a little at a time til they will chamber with some feel I can fire form them to the chamber with no problem. I can then neck size and fire the same moderate load and there are no flattened primers or any other signs of anything out of the ordinary. It will be getting the barrel set back and rechambered right after the first of the year.

Maybe it does have excessive headspace. If it does, you can still use it as is, if you load the way quarterboredave describes in his post.

A standard cartridge with excessive headspace is little different from an 'improved cartridge,' if the brass is only necksized after firing.

There is one thing that I am curious about, though, is how it developed excessive headspace. The only way I can see that happeneing is if the rifle was built on one of the softer 98 actions and either the bolt lugs or locking lugs set back. This is something you need to definately check for, and have corrected if you want to continue to use the rifle.

Thanks for your help. Does anyone have a guesstimate on the cost of having the barrel set back and rechambered would be?

$150.

Another option might be for you to rent a set of headspace gauges and check the rifle out yourself. http://www.reamerrentals.com/ProductDetails.asp?ProductCode=6Rem.g

At $5 for the rental, that is pretty inexpensive peace of mind.

If you take an unfired case and add layers of "scotch tape"
until you can just feel the shoulder touch that will be an
indication of the headspace with that case.
If you remove the firing pin and put the case directly under
the extractor this is an easy check.
Good Luck!
p.s. You will need a caliper to measure the tape thickness.

That's not really a "mild" load; it's 1.5 gr. under book max according to Hodgdon (IMR) data.

I use 44.5 gr. in a Ruger w/85 gr bullets for reference; not a hot load, but not real mild either.

Get the headspace checked muy pronto, and then size the brass accordingly as has been advised above.

MM