What now?

[hawken]

I'm developing a hunting load for my new Kimber Montana in 7-08
After breaking in the barrel I loaded 3 rounds each,
43.5gr, .9moa 2860fps
44gr, 1.3moa(max load) 2900fps
44.5gr, 2moa 2930fps
45gr, 1 moa 2980fps
45.5gr, 1.1moa 3030fps
46gr, 1.4moa. 3040fps Still no sign of pressure that I can see.
Nosler brass, 120 gr TTSX, RL15 powder, .050 off the lands.
So, my questions are.
Do I stick with 45.5 gr because of the 1.1 moa and speed and play with the bullet depth? Or, since there is no sign of pressure, try a bit more powder to get a bit more speed first?
Or what???
Next time I will be doing 5 shot groups.
Thanks

[Cowtown guy]

Originally Posted by hawken

I'm developing a hunting load for my new Kimber Montana in 7-08
After breaking in the barrel I loaded 3 rounds each,
43.5gr, .9moa 2860fps
44gr, 1.3moa(max load) 2900fps
44.5gr, 2moa 2930fps
45gr, 1 moa 2980fps
45.5gr, 1.1moa 3030fps
46gr, 1.4moa. 3040fps Still no sign of pressure that I can see.
Nosler brass, 120 gr TTSX, RL15 powder, .050 off the lands.
So, my questions are.
Do I stick with 45.5 gr because of the 1.1 moa and speed and play with the bullet depth? Or, since there is no sign of pressure, try a bit more powder to get a bit more speed first?
Or what???
Next time I will be doing 5 shot groups.
Thanks

Try that load but do 5 shots at 60 70 and 80 thou from the lands.

[DaleJ]

Originally Posted by hawken

43.5gr, .9moa 2860fps
44gr, 1.3moa(max load) 2900fps
44.5gr, 2moa 2930fps
45gr, 1 moa 2980fps
45.5gr, 1.1moa 3030fps
46gr, 1.4moa. 3040fps Still no sign of pressure that I can
Do I stick with 45.5 gr because of the 1.1 moa and speed and play with the bullet depth? Or, since there is no sign of pressure, try a bit more powder to get a bit more speed first?
Or what???
Next time I will be doing 5 shot groups.
Thanks

Not finding a node with R15, might want to look at R17. If you can't find R17 try 4350 or a real dark horse Win 760.
140 gr bullets will probably return better accuracy.

[wind drift]

With one set of 3 round groups, you really don't have the ability to reliably discern the true difference between any of the groups in the 0.9 to 1.4 inch range. I would do as you suggest and adjust seating depth for the 45.5gr load. Saying that, for a hunting rifle, you likely would never truly need sub MOA precision. If you feel like keeping it simple (and spend less on pricey bullets), you could just load up 10 or 15 more of the 45.5 gr load you have and confirm its pretty much a MOA load with 5 shot groups. Sounds like you have a nice shooting Kimber.

[kiwimike]

If the POI was quite similar for 45 to 45.5gr then there might be a node there. A place where even though pressure changes the POI is quite stable. If the groups are both quite tight but on different places on the target it not really a stable place. The speed's excellent, don't need more powder. Try 5 shot groups at 40' 50' and 60' off the lands with 45,5gr. Keep a close eye on pressure as it will go up as you get further from the lands (less case volume) and also goes up when you get closer to the lands (driving up the curb from a standing start).

If the groups start to tighten either way it might be the answer. 1MOA is good though.

Are there flattened primers or craters around the firing pin divet at 46gr?

[hawken]

If I overlay the 45 and 45.5 targets and pretend it's a 6 shot group, it would be 1.4 moa. POI pretty much the same.
The 46 primers look the same as the 43.5 primers. No flattening.
I think I'll load up 5 shots of 45.5 and different coal's. I'll let you know what happens.

Thanks guys.

[Cowtown guy]

Originally Posted by hawken

If I overlay the 45 and 45.5 targets and pretend it's a 6 shot group, it would be 1.4 moa. POI pretty much the same.
The 46 primers look the same as the 43.5 primers. No flattening.
I think I'll load up 5 shots of 45.5 and different coal's. I'll let you know what happens.

Thanks guys.

I have had great luck running them as far off the lands as 80 thou. Take a Mic with you. I would trust a Mic measurement of the brass, over flattened primers for pressure signs. Some primers are softer then others.

[u_cant_rope_the_wind]

R17

Wt. Bullet Powder Manufacturer Powder Charge Velocity (FPS)
110 Speer HP Alliant RL-17 50.5 3169
Remarks: Min OAL: 2.760; compressed charge
115 Speer HP Alliant RL-17 49.5 3107
Remarks: Min OAL: 2.655; compressed charge
130 Speer BTSP Alliant RL-17 48.5 3007
Remarks: Min OAL: 2.730; compressed charge
145 Speer BTSP Alliant RL-17 46.0 2819
Remarks: Min OAL: 2.730
160 Speer BTSP Alliant RL-17 44.0 2669
Remarks: Min OAL: 2.800
175 Speer GS Alliant RL-17 44.0 2574


Read more: http://www.loaddata.com/members/sear...=47&header=7mm Caliber Reloading Data#ixzz3Bm5ZCwBA

[gitrdun]

I would suggest that you try a little bit of a faster powder for the 120's. Try 4895, either H or IMR. That just recently has worked well for me with 120gr Nosler BT's. I don't shoot Barnes, but I know that they can also be "testy" with seating depth. Good luck.

[Dick284]

What Now!

Take your most promising loads, and shoot them repeatadly(5, 3shot groups or 3, 5 shot groups) at distances like 200, 300, and 400 yards.

This will tell you which ones are better.