PDA

View Full Version : OK, headspacing wierdness



antsi
02-08-2013, 06:05 PM
I posted here a while back about a cracked barrel nut on my early model 110 30-06, needing to replace it and re-headspace the rifle http://www.savageshooters.com/showthread.php?20074-Newbie-with-Cracked-Barrel-Nut

One of the gracious members here walked me through the headspacing process using two references: 1) cases previously fired in the same gun, and 2) using the factory iron sights as a reference to line up on.

I hadn't gotten around to shooting the gun yet, as I had also discovered a scope mounting problem and was waiting for some replacement parts from Burris.

In the meantime, I happened to wind up with a set of go/no-go gages and before trying out my rifle I decided to check it. The way I had previously put the rifle together, I was not able to close the bolt on the go gage.

It is very possible this is how the gun was previously headspaced - one of the oddball things I had previously noticed was the fact that I was having to size my brass a bit smaller than my Dillon case gage in order to close the bolt easily on this gun. In other words, I had noticed it seemed to be a tighter-than-spec chamber.

If I set the headspace according to the go gage, the factory iron sights do not line up - they're about 45 degrees offset (ie, the barrel is "unscrewed" about 45 degrees looser).

So the question is, what do I do now?
1) set the barrel the way it was - with the sights lined up and the chamber a bit too tight. This way the brass I've already sized would presumably fit. It wouldn't be a spec 30-06, but it should work with my ammo, right?
2) set the barrel correctly according to the go/nogo gages, and live with crooked sights (would this do something odd to the barrel harmonics?)
3) something else?

Speedrat1
02-08-2013, 07:23 PM
Just my opinion..... you have to make the decision on what's important to you! IF the sights are important to you line them up. If you can chamber factory then I'd stop with that, good enough. If you can't chamber factory rounds and you ever think there'll be a need then either rent a reamer for about $30 and take the 4 or 5 thou out or take it to a gunsmith that already has the reamer and let him correct it.
If you don't think you'll ever need to shoot factory ammo then just line the sights and continue to size to the chamber, there's certainly no harm in doing so. Should the rifle ever go to someone else though I think I'd pass the chamber irregularity along.

handirifle
02-08-2013, 07:32 PM
Yea I agree with speedrat. It sounds like someone swapped the barrel before, and figured lining up the sights (even though the barrel was from another rifle, most likely) was setting the headspace. I knew mine was good before for factory and reloads, cause I bought the rifle new in 74. Yours I believe was swapped from another gun, just my guess. If you like that barrel, and want the sights, I, personally, would have it reamed to correct specs WITH the sights lined up. That way if you ever forgot your ammo on a trip (not that I had ever done this :rolleyes: before mind you) at least all you'd have to do is buy local and re check zero, hunt saved.

goinssr
02-08-2013, 08:01 PM
I would not feel comfortable at all shooting a rifle that had improper headspacing. And headspace gages are the PROPER way to set headspace. I know there are other methods that folks use but I'm kind of anal when I put a barrel on and want it done RIGHT. If you have headspace gages then by all means use them to set the barrel.

Dennis
02-08-2013, 10:21 PM
I was taught by one of the best who is a member here. Stated: Always use a Go-Guage when installing a new barrel. It's your decesion on the No-Go Guage.

It might be only .001 or so, but the go setting is important enough to set it according to the guage. Surprisenly you still won't be able to close the bolt with the No-Go guage.

To get the sights correct, I personally would take it to a gunsmith as per Speedrat1 advice.

JMO

sharpshooter
02-08-2013, 10:51 PM
What makes you think that the gauges can't be incorrect? There is a tolerance on headspace gauges, and they will differ from manufacturers. if that is indeed the original barrel that come on that rifle, chances are that the headspace is correct, not considering someone may have changed the bolt head.

Dennis
02-09-2013, 12:08 AM
What makes you think that the gauges can't be incorrect? There is a tolerance on headspace gauges, and they will differ from manufacturers. if that is indeed the original barrel that come on that rifle, chances are that the headspace is correct, not considering someone may have changed the bolt head.

Sharpshooter, what is your recommendation?

stangfish
02-09-2013, 02:57 AM
20 threads per inch = .050 per one 360 degree rotation of the barrel. 45 degrees will go into 360 8 times. .050 divided by 8 means that in order to rotate the barrel 45 degrees to get the sights to lign up you will loose .00625 in clearance one way or the other. If you reload bump the shoulder back until it chambers and fire a round with the sights dead on, then measure the case headspace and compare it to a new piece or your sinclare gauge. lets see what you got here.

Stockrex
02-09-2013, 10:46 AM
Do you any fired brass from the rifle? U set the headspace according to what u load.
if it is non standard then u can only shoot those and not factory rounds