Anyone Know the 6xc's Throat Erosion Rate

[Mirage]

I have a new 30" barrel 1:7.5 chambered in 6xc for 115gr bullets. Touching the lands, the base of the bullet is in the case below the body shouder junction.
So I was debating throating the chamber deeper, but I don't know the rate at which the chamber is going to erode. It may be right where I would like it in 1000 rounds.
Anyone have info?
Thanks,
Ron W.
115 DTAC Touching Lands OAL = 2.698

 

[SHootSTraight22]

I have a new 30" barrel 1:7.5 chambered in 6xc for 115gr bullets. Touching the lands, the base of the bullet is in the case below the body shouder junction.
So I was debating throating the chamber deeper, but I don't know the rate at which the chamber is going to erode. It may be right where I would like it in 1000 rounds.
Anyone have info?
Thanks,
Ron W.
115 DTAC Touching Lands OAL = 2.698

I think you should be good.. What's your load and velocity?? I would be shooting pointed 105gr Berger Hybrids anyway...

 

[Mirage]

Current 30” barrel load:
Case: Norma 6xc. Case weight = 158.3< grns
Powder: 40.3 grns H-4831sc No pressure signs and low SD
Primer: Wolf LR
Bullet: Berger 115 VLD Jammed .045 to try to free up case capacity, 2.143 to OG. OAL = 2.807. The base of the bullet is at the bottom of the shoulder with this Jamb. Need a longer freebore and lead angle to make the 115s esp DTACs work.
2925 fps at 70 degrees.
At 41 grains I could see a faint ejector mark.
I would like to get the 115's to 3050 fps range, but the bullet is eating up case capacity.
So, it will not be possible as is.

 

[expiper]

op,,,whatever your FB is ,,,it is too short,,,as you have realized you are loosing case cap. because of bullet intrusion into the ctg case,,,,,it looks like your FB should be at least .050 longer,,,get a throater from Kiff (PT&G) and very CAREFULLY just two or three turns gently and then measure and do it again till you have the right depth,,,I set a bullet in the case where I want it and then run the throater in untill the ctg chambers fully ,,,with the bbl removed from the action,,,sort of use it like a headspace guage,,,I hope this makes sense,,,roger
PS...to answewr your question,,,,your ctg will prolly wear/erode the bbl ,,,.003" per hundred rounds,,,2000rds=.060"..

 

[DTubb]

FYI .160" of straight section and a 1 1/2 degree lead will be about 2.78" oal to be seated into the lands. Your less than 2.7" is about what a 107 should be.

Still shooting H4350 and S&B primers at 3040+ in a 28" barrel with no pressure signs.. most all of the 6XC users have too small a neck diameter and after 20 shots the carbon build up in the chamber neck influences the pressure..
Good luck
Dtubb

 

[r bose]

My 6xc is hard on the barrel. Krieger 7.5 TW is at 90 thousands erosion with 1236 round thru it. Load is 40g RL-17 with a 105 Hybrid or 38g with a 115 DTAC. Shoots unbelievably well but I hope to get 2000 round thru the tube.

P.S. I shoot prone matches, slow fire single loading, no rapid strings. After 22 rounds, you can't touch the barrel without getting scorched.

 

[AckleymanII]

Sounds like 17 eats barrels in this case????????

 

[Mirage]

Thanks for all the help Guys,
I had googled the topic, and posted here. I was seeing quotes of erosion rates from .00038 per round to .00004 per round.
I had decided .00006 per round sounded about right for this 6xc 115grn load.
So, I cut the throat about .045
Now the Berger 115 VLD OAL = 2.809 to the lands
115 DTAC OAL = 2.785 to the lands.
Actually the bullets were sticking and would have to bump the butt stock on the floor to get them out.
I have 20 rounds loaded that will jamb .010
I will do a load test jambing .030 since my last barrel liked it that way.
I did the barrel life calculator and it didn't look good. I hope I get 2000 accurate rounds out of it.
My loaded rounds neck = .270. Fired case neck is .2745. I should have .002+ clearance all around the neck. I will have to try the H4350. I just assumed it would be too fast a burn rate and the H4831sc would be better for 115s.

 

[Ledd Slinger]

Sounds like 17 eats barrels in this case????????

Although RL17 is one if my favorite powders for speed and accuracy in a lot of rifles, it really is hard on barrels. Anymore I only use it for hunting rifles because they dont see a ton of rounds downrange each year. Definitely would not recommend 17 in a varmint rifle or competition rifle if barrel life is a concern.

RL17 ate up one of my 6.5 Rem Mag barrels I liked to use for target shooting a lot in less than 800 rounds. Granted the 6.5 RM is a barrel burner when pushed to high velocity, but it burned it out so bad that there was no rifling for the first 3 inches. I should have kept an eye on it a lot earlier. Would have changed powders or at least slowed it down. Lesson learned the expensive way...

 

[tclaunch]

FYI .160" of straight section and a 1 1/2 degree lead will be about 2.78" oal to be seated into the lands. Your less than 2.7" is about what a 107 should be.

Still shooting H4350 and S&B primers at 3040+ in a 28" barrel with no pressure signs.. most all of the 6XC users have too small a neck diameter and after 20 shots the carbon build up in the chamber neck influences the pressure..
Good luck
Dtubb

I had a XC II reamer made from the 6mmar site and went with .120" FB and had a friend want a XC and throated for the Tubb 115`s and I went with an additional .050" for a .170" FB. Keeps the end of the bullet in the sized part of the neck.

 

[Iowa Fox]

My 6xc is hard on the barrel. Krieger 7.5 TW is at 90 thousands erosion with 1236 round thru it. Load is 40g RL-17 with a 105 Hybrid or 38g with a 115 DTAC. Shoots unbelievably well but I hope to get 2000 round thru the tube.

P.S. I shoot prone matches, slow fire single loading, no rapid strings. After 22 rounds, you can't touch the barrel without getting scorched.

What are some of the cooler burning powders for this 6mm?

 

[r bose]

Iowa Fox, H4350 has always been the go to powder for the 6xc but when mine was built powder was very hard to come by and the H4350 is still very difficult to find today. You have to stumble on it. That being said, I was pushing my 6xc to the upper limits with Rl-17 and it's really not necessary. I had the 105 hybrids going 3250 FPS with no pressure signs. Now I'm running them right at 3100 FPS to save barrel life.

 

[LitLBoy]

7828SSC works wonders in my 6XC ---- Why don't I hear of anyone else using this powder?
LitLBoy

 

[racesnake]

What bullet are you using with 7828, litlboy?