Short throated 260

[tiny68]

Helping a friend put together a long range hunting rig. Savage action with a CBI 24" 1:8 twist prefit barrel that is throated perfect for the 140 Berger Hunting VLDs. Then his wife decides she wants to play and whe gather components to put her a rifle together. Only prefit we could find was a MCGowen 1:8 260. Once installed he measures the distances to the lands and it is 0.075 shorter than the CBI. The end of the bearing surface on the 140 VLD is slightly below the neck shoulder junction. I have never had a bullet stuck this far in the case.

What is the acceptable practice when setting these long bullets in the neck. I think he should have the barrel throated to match his CBI but he is almost out of time before his shooting school.

Thanks, Tim

 

[barefooter56]

Tim,
Not acceptable. Take the barrel to a gunsmith and have him ream the throat. Make a dummy round with the base of the bullet about midway in the shoulder or a little less so he has a gauge to go by. You will have to discuss with him how far into, touching or far away from the lands you want.

 

[jsthntn247]

Is running at mag length a priority? Get it throated out and it might not fit inside a magazine.

 

[Sniper338]

It wont work with 140s!!! 140 bergers need extra long throat to shoot correctly in a 260!!

Tell the gunsmith/ get a 260 tactical chamber reamer... PTG... or get the specs from the 260 tactical reamer and tell the smith to make the free bore that long...

people have a hard time making 140s shoot in 260s... i see it a lot... thats what the 260 tactical reamer was designed to make shoot!!!

 

[tiny68]

Is running at mag length a priority? Get it throated out and it might not fit inside a magazine.

Yes - these will be hunting rigs in the end. The CBI barreled rig he can touch the lands with a COAL of right 3.000" and still cycle that in the factory DBM.

 

[rocknut]

I am having the same issue with a CBI barrel I have. It was SUPPOSED to come with a .160 free bore. After head spacing the barrel, I measured the distance to the lands using the Hornady comparator. I then loaded a round to that measurement. The overall length is still shorter than magazine length (2.80). The heel of the bullet is below the neck-case line. I placed a bullet next to the loaded case just to see how much more free bore I needed to get the heel of the bullet up to the neck-shoulder junction. I would have to move forward .100! So I called Josh at CBI to see what he had to say. He said it sounded like the barrel may have been reamed with the standard 260 reamer with a free bore of .118 I think. As I said, the match chamber is supposed to be .160. That's only .042 difference. But I would have to take the barrel off as the lot or batch number is under the barrel nut. This is a for a single shot target rifle so magazine length has nothing to do with it.

Luckily one of the guys in the club I belong to has a throating reamer and said he would throat it for me. This really helped me out as I have 6 matches I want to shoot this month and don't care to hand my rifle to a smith for a month in the middle of the season.

Anyway, I feel your pain. Good luck with your project, I hope it works out for you.

 

[rocknut]

I omitted that this was trying to use a 140 grain bullet in a 260 cartridge. Sorry about that.

Rocknut

 

[jsthntn247]

It wont work with 140s!!! 140 bergers need extra long throat to shoot correctly in a 260!!

Tell the gunsmith/ get a 260 tactical chamber reamer... PTG... or get the specs from the 260 tactical reamer and tell the smith to make the free bore that long...

people have a hard time making 140s shoot in 260s... i see it a lot... thats what the 260 tactical reamer was designed to make shoot!!!

Terry Cross's reamer is designed to be used with the 140's and stay under a coal of 2.850, so yes it can and does work well. However if the op's mag will cycle at 3.000 he should have it throated out.

 

[ballison]

FWIW, I just order a 260 reamer from PTG specifically for the Berger 140 Hybrid. After talking with Dave Kiff for quite a while, he recommended a freebore of .110". I believe the Tactical Match reamer has a .116 freebore. My COAL is going to be around 2.9", which will just fit into my mag.

The dimensions of the VLD should allow you to use a little more freebore and still seat them OK. The earlier question about mag length may be the deciding factor.Good luck!

 

[gunsandgunsmithing]

I'm of the opinion that, as long as proper neck clearance, dies, and sizing are used, the only significant thing throating longer will gain you is powder capacity. Anything else, in a hunting rifle especially, is debatable, at best.
With sufficient neck clearance AND dies that can be adjusted so as NOT to size all of the neck, any doughnut that may form will form on the outside and never contact the bullet. We can debate neck tension, combustion efficiency, etc, but remember, we're talking about a hunting rifle here. We don't often have the benefit of wind flags, concrete benches or perfect rest setups when hunting.


I believe that IF there is any benefit to "ideal" throating, it gets very much lost in the noise. OTOH, if one absolutely believes differently, use a long action for a 260 repeater. JMHO.--Mike