Short Chamber?

[Hobster]

So, I received my barrel today. It's chambered in .264LBC. I sent the company a bolt to ensure headspacing was correct during the build.
Put the gun together, and proceeded to check the headspace with Go/NoGo Gauges.

The go gauge was a No Go...

When attempting to load a round, the weapon will not go into full battery easily. When I had a spare Grendel bolt lying around, so I swapped that out for the 7.62 that I had the barrel headspaced to. Same result. The round gets stuck in the chamber, and requires implementing the "mortar" technique to get it out.

Upon inspection of the ejected round, the tip of the bullet has a mark in it. Looks to me like it's contacting the rifling.

I am using factory ammo. Hornaday 123Amax and Wolf 123 Gold Sp
Same results with both rounds.

Correct me if i'm wrong, but a .264LBC should shoot these factory loads just fine...
Here's a pic of the wolf bullet.

http://www.imageshack.com/photo/my-images/28/2013050423532457.jpg/

[ricsmall]

If it won't close on go gauge, it's too short

[stokesrj]

The bullet tip in your pic is independent of the chamber issue. It was nicked by a sharp lug on the barrel extension on the way in. The headspace is not set up correctly and needs to be returned if it won't close on a go gauge.
Bob

[Hobster]

Update:

I inspected the chamber again this morning in better light. There was a small burr of metal on the rim of the chamber.
After removing the burr, I can get it to go into battery, but it's pretty tight. I'm not sure how much force it should require, so I am still unsure if it's ok.

I also checked to see if it would chamber a round. It does this much easier now. (easier than the gauge) It still seems to hang up a little when trying to extract the bullet. I've determined that it's the bolt lugs contacting the barrel extension, because when the bullet is pushed in by hand, it slides right back out.

Since I have never headspaced a rifle before, I am unsure. Is the go-gauge supposed to be tight going in?

When chambering a bullet, I can push it into battery by pushing the back of the bolt carrier in with my thumb... maybe a couple pounds of force...

When chambering the go-gauge, I have to tap the back of the carrier with the heel of my hand to get it to chamber, and it is still a PITA to get out...

Oh, All of this is working with the Grendel bolt and not the 7.62 bolt that I sent to them... the 7.62 will still not go into battery

[Whelenon]

The go-gauge should not be difficult to close the bolt. It seems there is something fundamentally wrong. I would suggest going to your LGS or someone familiar with go no-go gauges and get an opinion.

[Hobster]

5 rds @ 100 yds gusty conditions.

http://www.imageshack.com/photo/my-images/109/20130505152306906.jpg

Seems to shoot OK. Roughly 1 MoA and only a few rounds out of the barrel.

Put 100 rounds through it without a failure.

Think I am OK?

After 100 rounds, I rechecked with the Go-Gauge. It's still tight. Not really sure what I should do here. It seems to shoot and function fine, but according to the gauge (assuming it's not supposed to be tight) I have a problem.

[LR1955]

5 rds @ 100 yds gusty conditions.

http://www.imageshack.com/photo/my-images/109/20130505152306906.jpg

Seems to shoot OK. Roughly 1 MoA and only a few rounds out of the barrel.

Put 100 rounds through it without a failure.

Think I am OK?

After 100 rounds, I rechecked with the Go-Gauge. It's still tight. Not really sure what I should do here. It seems to shoot and function fine, but according to the gauge (assuming it's not supposed to be tight) I have a problem.

Hobster:

Lets see now....... Bobby Stokes said it wasn't set up correctly. When you got it to close with effort on the Go guage, Whelenon said to take it to someone who is more familiar with checking headspace for his or her opinion.

And you want to know if you are OK?

You aren't until you bring it to someone who is experienced with checking headspace.

Short headspace will leave you open to an out of battery firing. When this happens, it will blow the ammo out the bottom of your magazine, shear a couple of bolt lugs, damage the bolt carrier, and probably damage the upper. Don't worry, a out of battery firing probably won't blow the upper apart. As for physical damage to you, most likely some burns on your face and cuts on your firing hand.

You may not get an out of battery firing with factory loads but it is only a matter of time with handloads if -- if -- the headspace is too tight.

LR1955

[Hobster]

I just got off of the phone with the guys who built the barrel.

They didn't set the headspacing to the 7.62 bolt I sent them. Instead, they used a 6.5 Grendel bolt that they had there.

I've already talked to a gunsmith, and am going to have it checked out tomorrow. We'll see what he says.

[Hobster]

Anothr update:
Had my gunsmith check it out. Chamber is good. However, the gauges i was using were junk. Actually out of spec... I guess be aware of PTG gauges.

I'll post pics with a real range report as soon as I can get out.

[Whelenon]

Not to second guess but I'm going to second guess. Your confident the gunsmith is correct, that the gauge were junk, that's good. My question, how did he check the chamber?

[Hobster]

Tbh, I have no idea how he checked it. I just gave him the gun and gauges. He called me the next day. I am very confident in this gunsmith. He's been in business for over 20 years,and has always done great work. He's actually the only one around that is familiar with the 6.5 Grendel cartridge.

[bwaites]

Interesting. I would wonder which chamber the PTG gauges you used were for? PTG has made various different "Grendel" reamers, including, I believe, the reamers for .264 LBC. If you got Grendel chamber gauges, and tried to use them in the .264 chamber, it might have caused the issues you had. There is only a little difference in the chambers, but there is a difference.

[Hobster]

Interesting. The gauges I have say 6.5 Grendel/.264LBC. I did have the rifle chambered in. 264. Maybe the ptg gauge is sort of a "happy medium"
Either way, I'm happy and can't wait to shoot!

[stokesrj]

PTG is the most respected name in gauges, chamber reamers, and precision tools. There is no difference between a 6.5 Grendel or .264 LBC when it comes to go, go-no go and field gauges, other than the name. They are the same because the difference is in the neck not the case body or shoulder. I feel very confident the problem is not with the PTG gauge as manufactured but it is very easy to damage a gauge and take it out of calibration without realizing it. I've seen people drop a .223 go or no-go gauge in a chamber and drop the bolt release. That gauge will be no longer in calibration from even one forceful chambering. These are precision instruments and must be treated with care.
The proper way to use one is to remove the bolt from the carrier, then remove the ejector, and ejector spring from the bolt. Insert the gauge into the bolt face so that it is captured by the rim with the extractor and held in place. Then by hand insert bolt and gauge gently into the chamber and attempt to rotate the bolt closed using finger pressure only. The go gauge should easily rotate into position. The go gauge may rotate into position with some force. That doesn't mean your chamber is to large it just means it is at max specification. Then you move to the field gauge and if it will rotate into position you have an over spec headspace.
I would suspect that if the gunsmith is a competent gun smith and says the gauge is bad, it probably is, but not because it was manufactured that way, because it has been mistreated. I hope this helps understanding this issue.
Bob

[ricsmall]

the chamber gauges should fit either one. the difference is in neck dia. and throat angle. But as far as body, the gauge will fit. The headspace gauge is measuring just that, headspace, which is the same in both chambers, its not accounting .005 neck diameter or compound throat angle.