What would be the easiest way to tune vertical out? 30BR H322 116gr bullets. The groups are 1 1/2 bullets wide but about 4/10 of an inch high very consistently. Seating depth , neck tension, powder charge ? This gun will shoot light bullets less than 112 gr into nice round groups. Suggestions?
Tuning Question
- Thread starter MRL
- Start date
jackie schmidt
New member
M
mks
Guest
It would be easier to say what does not affect tune. Pretty much everything in the whole rifle and rest system affects it - in addition to what you mentioned, flexibility of the stock, location of weight in the stock, the weight of the scope and how high it is above the receiver, where the rifle is positioned in the front and rear bags, etc., etc. How great is your extreme spread (ES) of muzzle velocity? Regardless of the dynamic response of the system, vertical is decreased with lower ES. If you want to learn how well the system is compensated for vertical, so that you have an idea of which way to change it, a ladder test is essential. Tune is also a function of temperature, so once you find it, keep notes on temperature so that you can find it again.
M
mks
Guest
1 1/2 bullets wide = 0.462", which is larger than your vertical. Is this what you meant?
R.G. Robinett
"That'll never work."
30 Cal groups just look BIG!
Per MKS, above, a thirty caliber group foot-print IS BIG - a 0.100" would measure .4 across the outside; are you talking center-to-center, or, outside spread? If the latter, you're not in bad shape you could be Agging .162, or so.
That said, especially with H-322 - I presume, the EXTREME version, neck tension is usually a good thing - lots of it!
With the relatively slow (for expansion ratio) powders (H-4198, RL-7, N-130, LT30, etc.) both Jam, & neck tension tend to reduce/eliminate vertical. When one goes to H-322, N-133, LT32, etc. - in a 30BR chamber - now, you're talking very SLOW! In other calibers - say, 6MMBR, all of these would be considered relatively fast burners - it's all about expansion ratio. (Note: burn rate chart comparison does not work across caliber (volume) changes - the 'closed bomb' test is a finite volume, & does not factor for expansion.) You certainly would not want to shoot a 22/6BR using 30 BR charge weights - you may well get hurt!
If you have .4" vertical C-to-C, you'll likely need to switch powder, or, fill the cases to about all they can hold, then compress the stuff, and hold the bullet where the barrel 'wants it' with enough neck tension. H322(EXTREME), N-133, etc., are, for the thirty caliber expansion ratio, nearing, "too slow" - especially with the lightest bullet weights. All of that stated, in the early 30BR early trials, I did manage to win a few tournaments using H-322(EXTREME), and shot a couple of .21xx (100Yd.) group Aggs to boot - MV was about 2920 FPS via 37+ Gr. of the stuff! Keep 'em ON the X! RG
P.S. I forgot - if your do not want to change powder, try some HEAVIER bullets - 125 Gr. are pretty decent . . . well, if one can tolerate the recoil!RG
Per MKS, above, a thirty caliber group foot-print IS BIG - a 0.100" would measure .4 across the outside; are you talking center-to-center, or, outside spread? If the latter, you're not in bad shape you could be Agging .162, or so.
That said, especially with H-322 - I presume, the EXTREME version, neck tension is usually a good thing - lots of it!
With the relatively slow (for expansion ratio) powders (H-4198, RL-7, N-130, LT30, etc.) both Jam, & neck tension tend to reduce/eliminate vertical. When one goes to H-322, N-133, LT32, etc. - in a 30BR chamber - now, you're talking very SLOW! In other calibers - say, 6MMBR, all of these would be considered relatively fast burners - it's all about expansion ratio.
(Note: burn rate chart comparison does not work across caliber (volume) changes - the 'closed bomb' test is a finite volume, & does not factor for expansion.) You certainly would not want to shoot a 22/6BR using 30 BR charge weights - you may well get hurt!If you have .4" vertical C-to-C, you'll likely need to switch powder, or, fill the cases to about all they can hold, then compress the stuff, and hold the bullet where the barrel 'wants it' with enough neck tension. H322(EXTREME), N-133, etc., are, for the thirty caliber expansion ratio, nearing, "too slow" - especially with the lightest bullet weights. All of that stated, in the early 30BR early trials, I did manage to win a few tournaments using H-322(EXTREME), and shot a couple of .21xx (100Yd.) group Aggs to boot - MV was about 2920 FPS via 37+ Gr. of the stuff!
Keep 'em ON the X! RGP.S. I forgot - if your do not want to change powder, try some HEAVIER bullets - 125 Gr. are pretty decent . . . well, if one can tolerate the recoil!
RG
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Ok
EPS 116gr. bullets
322 because this barrel loved this stuff with a Berger 110Gr bullet.
Vertical is center to center measured, horizontal is eyeballed 1 1/2 bullets wide outside to outside.
I have always had great luck using 322 in my 30BRs neck tension ranged from you could almost spin the bullet in the case to very tight neck tension .
I was just looking for a scientific wild ass guess . I will play with it more in the spring I have 1 more match this year and will finish my 112 Knights at it then the bullet hunt begins.
EPS 116gr. bullets
322 because this barrel loved this stuff with a Berger 110Gr bullet.
Vertical is center to center measured, horizontal is eyeballed 1 1/2 bullets wide outside to outside.
I have always had great luck using 322 in my 30BRs neck tension ranged from you could almost spin the bullet in the case to very tight neck tension .
I was just looking for a scientific wild ass guess . I will play with it more in the spring I have 1 more match this year and will finish my 112 Knights at it then the bullet hunt begins.
R.G. Robinett
"That'll never work."
jackie schmidt
New member
Usually, tons of vertices means you need to go up on the load. When you get it shooting reasonably flat, then you can work on the seating depth.
My 30 BR is very sensitive to seating depth. By sensitive, I mean the difference between a .280 rifle and a .180 rifle. But once you find it, it will stay there. You can shoot 250's all day long with a .280 Rifle, but to consistently hit 22+ x's, you need a .200 or better capable Rifle.
Set up a Chronograph, load it untill it hits about 3020 fps, and work from there.
Just my opinion, but I think the later Lots of 322 are a tad slow for a 30BR when using 112's on. 7 ogive 118's on a ten.
My 30 BR is very sensitive to seating depth. By sensitive, I mean the difference between a .280 rifle and a .180 rifle. But once you find it, it will stay there. You can shoot 250's all day long with a .280 Rifle, but to consistently hit 22+ x's, you need a .200 or better capable Rifle.
Set up a Chronograph, load it untill it hits about 3020 fps, and work from there.
Just my opinion, but I think the later Lots of 322 are a tad slow for a 30BR when using 112's on. 7 ogive 118's on a ten.
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