25x47 CBTO/COAL?

[wasskeet]

I recently bought a 25x47 barrel with a .180" freebore. I decided to look into getting some rounds loaded up a couple days ago. The .180" freebore seemed the way to go, however based upon initial findings - now I wonder. The 135 hybrid in the photo is loaded at .060" jump/off lands and I practically have no bullet in the case. Has anyone else ran into this issue? The cbto is approx. 2.295" touching lands.

 

[alphapygmy]

I used a JGS with .130 freebore and it was perfect for the 135 Berger. The bullet is sitting just above were a donut might form. The 135 CBTO at touch for me is 2.135 and .005 off the lands my OAL is 2.810. You might try the 134 ELDM, they have a longer bearing surface. If it was me I'd ditch the barrel and get one setup with better numbers. It costs money but how much are you going to spend trying to get that too long freebore to work and what happens when you need to seat the bullets out more for throat erosion? Just my .02.

 

[Coyote Shadow Tracker]

I used a JGS with .130 freebore and it was perfect for the 135 Berger. The bullet is sitting just above were a donut might form. The 135 CBTO at touch for me is 2.135 and .005 off the lands my OAL is 2.810. You might try the 134 ELDM, they have a longer bearing surface. If it was me I'd ditch the barrel and get one setup with better numbers. It costs money but how much are you going to spend trying to get that too long freebore to work and what happens when you need to seat the bullets out more for throat erosion? Just my .02.

If you haven't shot it yet go ahead. You might be surprised with the accuracy you get. I have had Ruger's with Freebore that couldn't be measured and shot in 0.0156". If it doesn't shoot get a new barrel!

 

[wasskeet]

Well, after meeting with a friend and his 25x47 w/ .130" freebore, we confirmed my cbto is exactly .050" longer than his. So good there now, but not going to be any .010"/.020" off with this combo. Got out for a starter trip and maybe learned a couple things about it.

 

[highdrum]

I run 135s jumping 55k in 180fb, shoots very well. E target from 650y.

 

[wasskeet]

I ran into another issue I didn't expect also - I thought Alpha brass wouldn't need trimming to start. Wrong on that.

 

[wasskeet]

I run 135s jumping 55k in 180fb, shoots very well. E target from 650y.
View attachment 652895

Looks like you have it doing very good! Are you running H4350, R16 or?

 

[highdrum]

Looks like you have it doing very good! Are you running H4350, R16 or?

38.7gr H4350 at 2760 fps. Honestly this cartridge shoots so dang good. Once I get the bullets back to 55k jump, powder doesn't even matter, it's just like pick your speed and go.

As to trimming, my chamber is headspaced pretty tight, virgin brass is only growing 0.0015, but I can still close the bolt on fired brass with slight resistance since my psi is so low. I sized a few cases and did exactly what you're seeing in the bore scope, and it looked like I didn't need to trim. However I did to uniform them all to the same size, chamfer and debur.

Heres a Pic of virgin, VS once fired/sized. Also included the reamer print for you.

 

[wasskeet]

Thanks for the info and print! I'd say H4350 is doing you right. Your speed is about where I want to be. I hope to get a few more rounds, maybe .055/.060/.065, down the barrel before a 1000yd match the end of this month. Not ideal by no means, but it is what it is as they say. I think the 25x47 is going to be a great cartridge.

 

[Tac284]

What barrel lengths are you folks running?

 

[highdrum]

What barrel lengths are you folks running?

28in, it's a match rifle. I've had it over 2900fps w/o psi tho.

 

[FEENIX]

Well, after meeting with a friend and his 25x47 w/ .130" freebore, we confirmed my cbto is exactly .050" longer than his. So good there now, but not going to be any .010"/.020" off with this combo. Got out for a starter trip and maybe learned a couple things about it.

If your goal is to get closer to the lands, try the 145 Black Hole bullets (https://blackholebullets.com/see-products). I load them in my .257 WBY, and I can touch the lands even with the long WBY FB.

 

[wasskeet]

26" here, but maybe have some issues

 

[Tac284]

Appears to be reamer bushing marks, guessing that is just in front of the throat?