Velocity related to neck tension? 6.5x47

[JerryK]

I just got back from Chrono testing my new BAT/ Broughton 31' 1-8 6.5x47 setup. I got up to 40.6 grains of Reloader 17 and the best velocity I got was 2600 fps, about 200-300 fps below what others are getting. It's a .290 neck, .288 loaded, 130 JLK bullet .010 jam into the lands. The only thing I can think of is I don't have enough neck tension, I'm using a .287 bushing. I can't move it with my fingers, but maybe it's releasing pressure before it builds? I got some primer flattening, nothing major. Everything is new so it must be me. Accuracy is good but I built this for 1000 yds, I need more velocity. Ideas?

 

[johara1]

I tried them all .287 .286 and .285 in a redding fl bushing die,none worked....... i now have a forster fl die removed the x ball that gives me .0025 neck tension and almost zero run out.......and it shoots RL-15 at 2897 av. for 10 shots with a jlk 130 in the low 2s sd was3 es 10. it will shoot faster but not that tight. one other thing i couldn't get rl-17 work.......jim

 

[jb1000br]

What chrono? Don't know that I'd believe those numbers

JB

 

[JerryK]

I'm using a Shooting Chrony, the base model. It does seem hard to believe, but I hate to blame the equipment.

 

[280man]

Try a different chronograph there is no way its that slow.

 

[JerryK]

I may have answered my own question. I went back to the range today with R17 and R15 loads, but this time I tightened the neck tension .001 with a .286 bushing. I went from jam to just kissing the lands. Yesterday I got an average of 2593 fps with 40.6 grains R17, today I got 2681 with 40.6 grains with the increased neck tension,gained 88fps). No pressure signs. That being said, I don't know if I can get enough R17 in this case to get to 2900--and get a decent group. However I did reach 2900 fps with 38.2 grains of Reloader 15, with a .350 inch 3-shot group. With 38.4 the group opened up for me, but more testing is needed. However, the R15 gave a lot tighter groups with all loads tested today. I will probably stay with R15. These loads worked for me, but this is an Ackley Improved version of the 6.5x47, so drive carefully.

 

[Dubya]

You will have to increase the amount of RE17. Have recently tested pretty much the same thing you have and find that 41.0
to 42.0 gr. will get you to 2950 or better with ES & SD in single digits.

Gary.

 

[rpl6cm]

I am having the same problem so I would like to ask a couple of questions.
To Johara1: - was the Forster die a custom die?
- have you tried Berger 130s?
- what load RL-15?

To Dubya: - what bullets are you using?
- what size busing or how much neck tension are you
using?

To anyone: -what group sizes are you seeing, and is there one
bullet weight that really stands out?

I have a Bat action, Shehane MBR stock, Bartlein 26' 8 1/5 twist. This thing should shoot better. Thanks

 

[Dubya]

I am having the same problem so I would like to ask a couple of questions.
To Johara1: - was the Forster die a custom die?
- have you tried Berger 130s?
- what load RL-15?

To Dubya: - what bullets are you using?
- what size busing or how much neck tension are you
using?

To anyone: -what group sizes are you seeing, and is there one
bullet weight that really stands out?

I have a Bat action, Shehane MBR stock, Bartlein 26' 8 1/5 twist. This thing should shoot better. Thanks

Hey rpl ! Am using Berger 130 gr. VLDs, a .288 neck bushing and
chronograph used is a Oehler 35P on a four ft. bar.
Just shot rifle at 1,000 yards for the first time on Sat,3-28-09
score=93 group size,,larger than I like), at 11.120'- will have to sdjust seating depth and maybe powder load, will do some more testing. Rifle is built on a Lawton 7500 action rb/rp/re and recently changed from Krieger,28') 8tw bbl. to Shilen 9tw at 28 in.
Gary.

 

[lmorrison17]

25' barrel 8.5 twist, berger 130 VLD, 42.1gr H4350,RL-15 did not work for me, Varget was good but nothing shot like the 4350) is getting 2860. Varget and RL-15 were faster but didn't group as well. I think your barrel is too long, friction drag. But seriously don't get hung up on velocity, I did at first too. How well does it group?
Larry

 

[JerryK]

I think friction was a factor at first, three trips to the range later I'm getting 3010 fps with a .375 3-shot group. I think the barrel just needed breaking-in. That's with 38.5g Reloader 15, touching the lands, .286 bushing,.288 loaded in a .290 neck. I was hoping for velocity to help with wind drift at 1000 yards.

 

[johara1]

rpi6cm, that die is a forster fl die with the expander removed. i have a .290 neck in the chamber and the case necks are turned to .012, so a loaded round is .288. the die sizes to .285 and zero run out.not bad for a factory die and not i have a second die,it's going back to be opened up...it also has very low run out........the jlk shoots better than the bergers........jim

 

[rpl6cm]

thanks guys for all the help. i will be making up another round of various charges with the RL15 this week. i don't want to use any more than .002' neck tension so i suppose it it just going to be an increase in charge wt. i notice most people are using about.5grs. more than i am. i did notice great grouping at the lower velocities,.23' @2750-2815fps) with the berger 130s. it seems like there should be another node at 2950-3025fps, thats what i am aiming for, but if they don't group i'll just shoot slower. the other thing is this barrel only has 275rds through it. is should be broken in by now,right? lets keep talking. thanks again.