6mmbr varmit load help

[Fritts679]

Need some advise on a xp-100 action 6mmbr with 20" 1:14 twist barrel. The problem that I have is the bullet I'm trying to use (55gn nosler bt) will not reach the lands. I just want to know if this is normal. I have been loading 70gn nosler bt and using the coal specified in nosler book 2.200 and it has been accurate I'm just trying to improve it. If I need to list more info please tell me what. I just want to know if something is not right by not being able to touch the land or even get close to touching. Any help or guidance will be much appreciated. The load I'm trying to work up is 55gn nosler bt, h322 with br4 primer. If someone could also tell me how to identify what type of barrel I have that would be great too

 

[rifleman700]

Need some advise on a xp-100 action 6mmbr with 20" 1:14 twist barrel. The problem that I have is the bullet I'm trying to use (55gn nosler bt) will not reach the lands. I just want to know if this is normal. I have been loading 70gn nosler bt and using the coal specified in nosler book 2.200 and it has been accurate I'm just trying to improve it. If I need to list more info please tell me what. I just want to know if something is not right by not being able to touch the land or even get close to touching. Any help or guidance will be much appreciated. The load I'm trying to work up is 55gn nosler bt, h322 with br4 primer. If someone could also tell me how to identify what type of barrel I have that would be great too

Unless you have a very short freebore or zero freebore yes, this is common. My suggestion is to load it as long as you can where it still has good neck tension to hold bullet in place and then start your powder testing at this length. Once you find the powder charge you like you can then begin to seat it deeper in the case to do seating depth testing. The more bearing surface / neck contact the better. Loads do not have to be in the lands to shoot well.

With H322 your max velocity will be around 3600 fps with a 20" bbl. This should be around 33.7 grs. Load to velocity not to charge weight.

 

[RonAKA]

Need some advise on a xp-100 action 6mmbr with 20" 1:14 twist barrel. The problem that I have is the bullet I'm trying to use (55gn nosler bt) will not reach the lands. I just want to know if this is normal. I have been loading 70gn nosler bt and using the coal specified in nosler book 2.200 and it has been accurate I'm just trying to improve it. If I need to list more info please tell me what. I just want to know if something is not right by not being able to touch the land or even get close to touching. Any help or guidance will be much appreciated. The load I'm trying to work up is 55gn nosler bt, h322 with br4 primer.

Essentially your problem is that the throat of the chamber is too long for the twist of the barrel (14), and the short length of bullets suitable for a 14 twist. I have a 12 twist 6BR that has a long throat. It will shoot 68 grain Bergers down into the 3 shot 0.1's for group size. However when I go to a shorter 62 grain bullet, the group size explodes to 2" plus.

Unless you change the barrel, you will have to work with what you have. First I would determine what bullets are suitable for your 14 twist. I rather doubt 70 grain bullets will be, and especially boat tails. You may be better trying flat base bullets in the lighter weights, although with the long throat, the longest and heaviest bullet you can stabilize will likely be the best. Here is a calculator that you can use to evaluate bullets providing you have the dimensional data. Put in your 14 twist limitation, and then try different bullets. Ideally you want a stability factor of 1.5 at the muzzle velocity you are actually getting, but as low as 1.2 might work too.

Kolbe Barrel Twist Calculator

Or, you can just look at Berger's recommendations for bullets:

Berger Quick Reference Chart

The 62 to 68 grain flat base Target bullets may work, but no chance with the heavier boat tails. You could consider the 69 grain high BC flat base varmint. I have shot that in my 12 twist. Might work in a 14. Berger recommends 12. The problem I had with it was that with the high BC profile it is "short" to the ogive, and I had a hard time getting it to the lands in my gun.

 

[Fritts679]

Thank you for your replies. Very helpful. I would also like to get some opinions on what type of barrel to get if I wanted to replace it (brand, length, twist etc.). I would be using the gun for prairie dogs and maybe coyotes. The average shot would be 150-200 yards and on a good day we shoot 250 rounds

 

[powderbrake]

As previously stated, your twist is too slow for a bullet that would reach the lands. If you are only shooting to 250 yards, a 223 would be a great caliber for you, but you have a larger bolt face with the 6mm BR.

I shoot a 6mmBR for prairie dogs, and use a 28" Krieger barrel with a 1:8 twist, using Berger 88 gr Varmint bullets, 31.7 gr Varget, and it shoots groups in the .1 to .2 range.

 

[RonAKA]

Thank you for your replies. Very helpful. I would also like to get some opinions on what type of barrel to get if I wanted to replace it (brand, length, twist etc.). I would be using the gun for prairie dogs and maybe coyotes. The average shot would be 150-200 yards and on a good day we shoot 250 rounds

The only real technical problem with your existing barrel is that the throat is too long for the light bullets needed by a 14 twist. If you want to stay with the shorter lighter bullets, one option would be to have the chamber set ahead so the throat length is suitable for the lighter 60-70 grain bullets which your 14 twist can handle.

 

[2dogs]

Have you tested your "short bullet" load? It might surprise the heck out of you.

 

[Fritts679]

I haven't tested them yet but I'm planning to next week. I loaded several different wieghts of powder to try.

 

[rifleman700]

A set back to a .020" minimum spec freebore is what would be ideal. The money you spend on bullets and powder could be used to set it back.

 

[John Russell]

Thank you for your replies. Very helpful. I would also like to get some opinions on what type of barrel to get if I wanted to replace it (brand, length, twist etc.). I would be using the gun for prairie dogs and maybe coyotes. The average shot would be 150-200 yards and on a good day we shoot 250 rounds

Fritts...

One of the problems with reading these "Accuracy" sites is they leave you with feeling that if everything about your rifle isn't abso-friggin'-lutly P-E-R-F-E-C-T, then you need a new rifle, new barrel, a new everything.

Nothing could be further from the truth.

Your targets and ranges would be well served by an over the counter rifle, with an 8 power scope - to consider spending $500+ to replace a barrel because of a 10 to 30 thou jump to the lands is pure crazy, and bad advice.

Load your loads, enjoy your rifle, and kill your little beasties !!.

 

[snert]

Yes, try it first..work with it a bit. Often times you will find that the PD exit polls indicate no preference in barrel bullet selection....