Gunsmithing Used AI barrel chamber issue

[Terminator2]

I bought a used Krieger 260 Rem barrel off ebay for my AI/AT. It was chambered by Moon at Crescent Customs. The seller posted pics of the great groups it produced. I got it and it looks to be in good shape. I bought some Lapua brass and a set of dies for it. I seated a Hornady 140 ELD on of the new empty Lapua cases to a COL of 2.80" and tried to chamber it and it was a no go. I then full length sized the new Lapua case reseated the 140 ELD and tried chambering again. It would chamber, but it took effort to chamber and to close the bolt. Should I try bumping the shoulder back on the new brass or is there something else I should consider doing? Thanks in advance for any suggestions.

 

[Pinmaster]

I am paranoid... so I would slap a headspace (GO) gauge in it if it were mine. I have a set of 6.5 HS gauges for that very reason. I have a used moon AI barrel and it passes on GO & NO-Go. Is the chamber clean? carbon build up or oil can cause the chamber to be tight.

 

[ShtrRdy]

Have you tried just chambering a piece of new brass without the bulet?

 

[Terminator2]

Just tried an empty new Lapua case and it did chamber although very tight. I bought some commercial .260 rem tonight and tried it and it chambered it ok but still tight. I guess it's OK. I'm use to a lot less bolt closing force on my .308 and 6.5 Creedmoor factory AI barrels. I guess some chambers are tighter than others.

 

[jbell]

I would remove the firing pin assembly first (so you can actually feel what is going on). Measure the shoulder on the new brass and bump it 0.001" until the bolt closes the same as it does on an empty chamber. Then you know what your dealing with & can decide what you need to do from there...

 

[ShtrRdy]

On the AI AT rifle, place the safety lever in the middle position. It should be very easy to close and open the bolt. How does it feel without any case inserted?

 

[RTH1800]

Moon is very highly regarded and will likely be glad to check this out.

 

[Terminator2]

I just tried chambering again a new Lapua case, this time with the safety in the middle postion as suggested (which held the firing pin back) It went in smooth and the bolt closed smoothly. I then tried feeding from the magazine a new Federal Fusion 120 gr cartridge, again with the safety in the middle postion and while it chambered ok, the bolt closing was still somewhat tight. I think I'll try resizing another case and bump it back .001 as suggested and give that a try before buying and waiting for "go" and "no-go" gauges. I contacted the guy I bought the barrel from and he said that he didn't experience the tightness in his AI that I'm experiencing. His AI was not the AT model I have, rather the older model that required a barrel wrench for barrel removal. I do appreciate all of your helpful suggestions...thanks!

 

[EXTREMEPREJUDICE]

I would suggest you identify why factory brass is hard to chamber. The go gauge would be my first choice. As already suggested, you can continue to size your brass until it "seems/feels" to chamber, but then you would have to use a comparator or case gauge to see where you really are (because I imagine, you want to be in spec?) It's possible that although it was fine with the sellers bolt, receiver, load, etc., it might be short chambered for your rifle, especially since it was aftermarket and not AI (I am not questioning the smith that chambered the barrel or his ability as his reputation is well known) it could have been chambered with certain specs in mind.

 

[ShtrRdy]

I have another idea of something to try. Take the barrel off the action and first try dropping a new case in the chamber. My guess is it will drop right in without needding a push. Then try dropping in the Federal Fusion 120 gr catridge. Does this one also drop in without needing a push? It should fully drop into the chamber without interference.

If the Federal Fusion cartridge does not fully chamber we need to figure out where the interference is coming from. Take a permanent marker and color the bullet and first 1/3 of the case. Place it in the chamber with moderate pressure and then pull it out. Are there any areas that were colored where the color has been rubbed off or smeared?

 

[Terminator2]

Another great suggestion. When I dropped both the loaded cartridge and the new empty into the detached barrel they both dropped in without any resistance. I then tried this: I screwed the barrel back into the receiver and rather than putting a lot of torque on it when it bottomed out, I just let it make contact, and tried chambering a loaded cartridge and wala, it chambered just fine! So, I'm beginning to think that my extra tightening of the barrel in to the receiver altered the chamber distance and caused the tightness. Does this sound to be a reasonable explanation?

 

[ShtrRdy]

It seems like you should be able to tighten the barrel, and then the cross bolt, and still be able to chamber a factory round.

So, please do another test -- tighten the barrel onto the action, and tighten the crossbolt. Then try to close the bolt without a empty case or cartridge. Have the safety lever in the middle position. How does the bolt feel closing and opening?

 

[Terminator2]

ShtrRdy, I tried your test and the bolt closes smooth as butter with the safety in the middle position. I'm going to have a local smith take a look at it and check the headspace. Spartan Rifles is about 10 minutes away, and hopefully he can squeeze me in to look at it. Anyway, thanks to all for your insight , suggestions and recommendations, they were all welcome and appreciated. This is a great community!

 

[buffybuster]

You sure you're not jamming the bullet into the lands?

 

[Terminator2]

No, as I've tried it with brand new commercial ammo and even and empty new case and new case sized. No marks on the bullets at all.

 

[buffybuster]

Sounds like maybe the base of the chamber is too tight.

 

[Terminator2]

I took the barrel and rifle to Spartan Rifles yesterday and had Mark look at it. It wouldn't close on the "go" gauge. Diagnosis is that the chamber was too short and the throat had significant erosion and fire cracking. We decided to cut off 1 1/2" at the breech and rechamber it. I don't think I'll buy another used barrel on ebay again. Live and learn.

 

[ShtrRdy]

Thanks for the update. It's a bummer it ended up this way.

How many rounds did the seller say was fired through it?

 

[Terminator2]

In his description he wrote "unknown rounds". I should have remembered that old latin phrase, "caveat emptor". But on a positive note, since I got it for $225 and Mark's work will be another 2 bills, when I get it back it will still be a bargain as it is already fluted and threaded for a brake.

 

[Pinmaster]

Let us know how it shoots after it is set back... I hope that it performs well for you.

 

[Terminator2]

Will do. Thanks again to all.

 

[McCrazy]

In his description he wrote "unknown rounds". I should have remembered that old latin phrase, "caveat emptor".

"Unknown rounds" is bullshit and should have prompted a follow-up question asking for an approximation.

There is a big difference between 300 rounds or 3,000 and I bet the seller had a pretty good idea the barrel was thrashed. Find his address and bash him in the shins with the barrel...

 

[Terminator2]

Yeah, in hindsight, I agree I should have asked a few more questions, but it is what it is now, and since the seller is in Texas and I'm here in California, I think the shin bashing idea, is a bit impractical. Thanks for your thoughts on the subject though.

 

[Brux]

Something is not right. If the throat has firecracking ,that means the barrel has been shot a lot. Right? If the chamber was cut to short how would the seller of the barrel have been able to shoot it so much?

 

[Terminator2]

From my understanding, fire cracking can also occur from hot loads and rapid firing without a cool down. From the sellers description, I assumed that he was not the original owner of the barrel. He wrote that the loads he fired were 136 scenars at a little over 2900 fps with 43.2 gr of H4350. He also showed pictures of the groups from his testing of these loads. Of course, buying on ebay, you only have the sellers word for all of this.

 

[Brux]

The chamber head spaced correctly with the bolt that the seller had and not the bolt that the OP has.
If it was short chambered from the beginning, the seller would not have been able to shoot out the barrel without all the problems that the OP has have.
The barrel's headspace should have been checked when the OP bought the barrel with his bolt.
Moon is great builder and would not have let a barrel go out of his shop that was not correct.

 

[Terminator2]

Things to keep in mind.
1. I bought this used barrel on ebay from a seller in Texas and I am in California so I was not able to check the headspace with my bolt.
2. Mark at Spartan Rifles checked the barrel on my AI AT with a .260 go gauge and it would not chamber on my rifle.
3. The ebay seller is the one that claimed that Moon did the chambering, so again, it is ebay and sellers may or may not be telling the truth.