Working up a 6.5 Creedmoor load.

[dsdmmat]

Trying put out the Sierra 142 HPBT over IMR-4350 and a CCI large Rifle Magnum primer.

Loading for both the model 10 and model 12 the head space is .0025 different and the lands are .011 different between the two rifles. The Redding competition die and shell holder set makes loading for both rifles at the same time easy.

I am starting at 38.5 grains and going up in .5 grain increments until I hit 41.5 which is about a grain shy of max to take into account the hotter primer. I hope to get out to the range in the morning and see how they group at 200 yards. It would be really convenient if both rifles like the same powder charge. What are the odds of that.

 

[ProgSpear]

looking forward to your analysis. Just bought a 10 BA in 6.5 CM. Haven't had a chance to shoot it yet. I'm itching...

I plan to shoot Hornady factory loads initially, but I'm in the process of setting up my load station again (after a lot of house renovation) and would really like to dial it in.

dumb question (i'm good at them) but what's your procedure for checking the seating?

 

[dsdmmat]

looking forward to your analysis. Just bought a 10 BA in 6.5 CM. Haven't had a chance to shoot it yet. I'm itching...

I plan to shoot Hornady factory loads initially, but I'm in the process of setting up my load station again (after a lot of house renovation) and would really like to dial it in.

dumb question (i'm good at them) but what's your procedure for checking the seating?

bullet comparator - Google Search: use one of these with the bullet you intend to shoot. Slide it up into the lands and then measure it then I back it off 10 thousands of an inch.

 

[ProgSpear]

LOL, you correctly answered the question I asked incorrectly, and I got good information, just not for what I wanted to ask.

I'll try again. How did you determine there was a .oo25 headspace and a .o11 land differential between the two rifles? What tools/procedure is required to determine the headspace and jump (correct term?) for a specific rifle?

 

[dsdmmat]

LOL, you correctly answered the question I asked incorrectly, and I got good information, just not for what I wanted to ask.

I'll try again. How did you determine there was a .oo25 headspace and a .o11 land differential between the two rifles? What tools/procedure is required to determine the headspace and jump (correct term?) for a specific rifle?

Head space gauges are used to measure fired cases, I measured fired cases from both rifles. I used a bullet comparator to check the lands in both rifles. Just comparing the measurements between the two samples told me the difference between the two rifles.

 

[dsdmmat]

Well the model 10 likes em hot and the model 12 likes em moderate. The best group for the model 12 was 1.443 inches with 40.5 grains IMR 4350 and the model 10 had a group of 1.355 inches at 41.5 grains of IMR 4350. These groups were shot at 200 yards and shot in a string ( one from each powder weight was fired low to high then reversed high to low)

Shooting the strings this way allows for human error to be introduced. This also shows me which is the most consistent group. I fired 7 shots, swapped rifles fired 7 shots from it and repeated until all 35 from the test for each rifle was done.

I may go up another grain for the model 10 and see if it likes them hotter. Once I settle on a load I will fire them over a chrono and in groups of 5 to see how well they perform. I will play with the loads in .3 increments and may push the bullet further into the lands to see if the groups tighten up. But both groups we 3/4 MOA so they will be a good starting point to work with.

 

[squib]

Any pressure signs at the higher nodes? I am helping a friend with a 140gr load and H4350. We are making crunchy loads without and visible signs of pressure.