Short throat issue, rifle wont chamber anything with a COAL over 2.245

[nexgen91]

I recently purchased a new 20" barrel for my Grendel build and ran into issues with it, returned for a replacement and having issues with the replacement barrel also. I have done some more extensive troubleshooting with the second barrel outlined below, and would like to get input from the horde...

The new barrel refuses to chamber anything with a COL/OAL of 2.245 (at this length it takes more than normal force to pull back charging handle, if I load them longer than this I have to hit the charging handle with a mallet to get the round out of the chamber. After reading a bit, I have came to the conclusion that this will prove to be problematic with some factory ammo (which I would like to be able to use any of at times, when I am short on time to reload).

I decided to get some OAL measurments using the Hornady OAL gauge and #6 bushing, I made some dummy loads using Hornady 123gr ELD-M and Starline brass. I took some measurements and am averaging (over 6 measurements) 2.232" OAL from tip and 1.707" from ogive to cartridge base (full measurements below).

From rim to ogive
1.730
1.699
1.704
1.705
1.704
1.699
1.707 <--Average

From rim to tip
2.239
2.220
2.230
2.237
2.233
2.230
2.232 <--Average


Some of Lyman's loads state 2.260" as the max COL/OAL which I assume I would like to be able to load to if needed, which is not the case. It appears the chamber is out of spec. I am not sure it would be worth it (to me) to get it reamed to correct the chamber. Any input from y'all would be appreciated. The barrel is one of the monster (green mountain) barrels, and John (BluntForceTrama) has been working with me and doing everything he can to help me out.

[mv1arms]

I recently got the 18" and no issues with chambering so far with factory loads: Hornady SST, ELD match, Federal 130 berger, Federal fusion, Federal AE 120 grain. But I will check a bunch of reloads with COL of 2.26" in the chamber tonight and get back to you. I have a lyman MSR cartridge ammo checker block and the reloads all were OK with that.

[nexgen91]

I recently got the 18" and no issues with chambering so far with factory loads: Hornady SST, ELD match, Federal 130 berger, Federal fusion, Federal AE 120 grain. But I will check a bunch of reloads with COL of 2.26" in the chamber tonight and get back to you. I have a lyman MSR cartridge ammo checker block and the reloads all were OK with that.

Ok sounds good, looking forward to what you find. I also checked all my loads with the MSR checker block and had the same results.

[grayfox]

Did you mark the ogive/transition area of the bullet with a sharpie and load, then extract to see any rifling marks?

[A5BLASTER]

If your barrel jam's the bullet of any factory ammo. It's got a short throat and needs to be fixed or replaced. Since you stated this is a replacment barrel already and it's doing the same thing.

It's time to cut bait and walk away. Either send it back and ask for a refund or buy a new barrel from a diffrent company, install and move on.

Fireing a round from a barrel that has a short throat and jam's bullets of factory ammo is a dangerous weapon and shouldn't not be used.

[grayfox]

I was going to add... some kinda bad news.... if the chamber is nitrided it is probably impossible (or nearly so) to change its dimensions. The nitriding makes the surface verrrry hard, anyway from what I've read. Now if by some stroke it is possible then I'll bow to superior knowledge on it, not being dogmatic, just from what I've seen on the nitriding...

[nexgen91]

If your barrel jam's the bullet of any factory ammo. It's got a short throat and needs to be fixed or replaced. Since you stated this is a replacment barrel already and it's doing the same thing.

It's time to cut bait and walk away. Either send it back and ask for a refund or buy a new barrel from a diffrent company, install and move on.

Fireing a round from a barrel that has a short throat and jam's bullets of factory ammo is a dangerous weapon and shouldn't not be used.

This is along the lines of what I am thinking, I want to be able to use any factory ammo (I am willing to sacrifice the small amount of accuracy this may affect, as I am not competing or anything anyway).

I was going to add... some kinda bad news.... if the chamber is nitrided it is probably impossible (or nearly so) to change its dimensions. The nitriding makes the surface verrrry hard, anyway from what I've read. Now if by some stroke it is possible then I'll bow to superior knowledge on it, not being dogmatic, just from what I've seen on the nitriding...

Interesting, the barrel itself is nitrided (not sure about the chamber).

[grayfox]

Generally the entire barrel, inside and out, is nitrided as it is done at a high-temp salt-bath style of process...
I'm sure BFT will work with you... if nothing else seems to help maybe they would do a simple SS barrel for you, then if it's short-throated you can have it finish-reamed to spec. Just an idea.

[nexgen91]

Generally the entire barrel, inside and out, is nitrided as it is done at a high-temp salt-bath style of process...
I'm sure BFT will work with you... if nothing else seems to help maybe they would do a simple SS barrel for you, then if it's short-throated you can have it finish-reamed to spec. Just an idea.

That's what I was thinking �� Yeah he is being super helpful in trying to figure out what is going on, I would be ok with a SS barrel if need be. It is a nice barrel/bolt and I want it to work.

[mv1arms]

I confirmed no issues chambering 2.26" reloads in my Group Buy 18 inch, multiple bullet types tested.

[muvef]

I recently purchased a new 20" barrel for my Grendel build and ran into issues with it, returned for a replacement and having issues with the replacement barrel also. I have done some more extensive troubleshooting with the second barrel outlined below, and would like to get input from the horde...

The new barrel refuses to chamber anything with a COL/OAL of 2.245 (at this length it takes more than normal force to pull back charging handle, if I load them longer than this I have to hit the charging handle with a mallet to get the round out of the chamber. After reading a bit, I have came to the conclusion that this will prove to be problematic with some factory ammo (which I would like to be able to use any of at times, when I am short on time to reload).

I decided to get some OAL measurments using the Hornady OAL gauge and #6 bushing, I made some dummy loads using Hornady 123gr ELD-M and Starline brass. I took some measurements and am averaging (over 6 measurements) 2.232" OAL from tip and 1.707" from ogive to cartridge base (full measurements below).

From rim to ogive
1.730
1.699
1.704
1.705
1.704
1.699
1.707 <--Average

From rim to tip
2.239
2.220
2.230
2.237
2.233
2.230
2.232 <--Average


Some of Lyman's loads state 2.260" as the max COL/OAL which I assume I would like to be able to load to if needed, which is not the case. It appears the chamber is out of spec. I am not sure it would be worth it (to me) to get it reamed to correct the chamber. Any input from y'all would be appreciated. The barrel is one of the monster (green mountain) barrels, and John (BluntForceTrama) has been working with me and doing everything he can to help me out.

Those are some crazy base to ogive measurements. I've never seen variations greater than .0015" when measuring where the ogive touches the rifling on any of my barrels.

On the cheap you can cut the neck of a resized case and shove it in your chamber. Push it out gently with a cleaning rod. Do this several times to come up with your average. I have the 18" group buy barrel and a 123 ELD touches the lands at 2.310" COAL every time. Green Mountain checks their chambers and I would be surprised if they sent a couple out that weren't exactly the same as the others.

OAL-3.jpg

[Hawk518]

I am having a similar issue with my radical firearms 20inch. Max COAL was 2.243 for hornady black ammo. that was leaving lands marks on the bullet. Hornady ELD Match bullets are my reload go to, and i cant use them. I just spoke to my barrel manufacturer and they are going to re-throat my barrel free of charge. They are a stand up company and are great to deal with. I will give details after the transaction is done!!

[nexgen91]

I am having a similar issue with my radical firearms 20inch. Max COAL was 2.243 for hornady black ammo. that was leaving lands marks on the bullet. Hornady ELD Match bullets are my reload go to, and i cant use them. I just spoke to my barrel manufacturer and they are going to re-throat my barrel free of charge. They are a stand up company and are great to deal with. I will give details after the transaction is done!!

That's good on Radical to take care of you like that 🙂I ended up returning my barrel and put a PF Criterion barrel on order. I got tired of troubleshooting and didn't want to deal with unknowns from other barrel makers, PF has a good reputation so I went with them. I previously had a Radical 24 inch upper, and while I was happy with how it shot, I wanted to get a shorter barrel.

[Hawk518]

update on radical firearms 20 inch stainless barrel. before measurements 123 eld match 2.230 COAL now 2.256 COAL / 120 eld match 2.150 COAL now 2.187 COAL / Ogive is 123 1.669 120 1.646

I didn't have comparator before i sent it back so i dont have the pre ream measurements.

It still dosent meet the hornady manual 10th edition for COAL of 2.245 for 120gr. ELD match but it exceeds it for the 123gr.

Guess i will have to stick to 123gr. unless hornady wants to buy me a new rifle that can shoot those 120gr eld with their manual specs.

to the range Monday and test it out!!

[nexgen91]

update on radical firearms 20 inch stainless barrel. before measurements 123 eld match 2.230 COAL now 2.256 COAL / 120 eld match 2.150 COAL now 2.187 COAL / Ogive is 123 1.669 120 1.646

I didn't have comparator before i sent it back so i dont have the pre ream measurements.

It still dosent meet the hornady manual 10th edition for COAL of 2.245 for 120gr. ELD match but it exceeds it for the 123gr.

Guess i will have to stick to 123gr. unless hornady wants to buy me a new rifle that can shoot those 120gr eld with their manual specs.

to the range Monday and test it out!!

Thanks for the update 🙂