some range data and a few questions

[mnhntr]

Ok so I went out on a really nice day to get some time behind my LRP. I got it in the fall, and did not get a lot of range time with it over the winter. Working up loads in the fall I got less than good groups with H4350 and 140gr Berger VLDs. I tried different seating depths and charges. I ordered some SMKs 142gr, and set out to the range today.
This is the load particulars: 142gr SMK, H4350 powder, Winchester 7mm-08 brass necked down, Federal Match primers. The SMK's all got seated at 3.280 in. The best was the second group then it seemed to open on the third and start to tighten on the fourth. The fourth is max but there were no pressure signs so I am going back tomorrow with 44.7gr and 44.9gr to try them.


1) 41.5gr H4350
Avg 2730 fps
33 ES
14 SD

2) 42.5gr H4350 (Best group)
Avg 2775 fps
41 ES
15 SD

3) 43.5gr H4350
Avg 2863 fps
30 ES
11 SD

4) 44.5gr H4350
Avg 2918 fps
26 ES
10 SD

Now the questions. Do you clean and foul before each group when working up a load?
How many rounds before cleaning when working up a load?
How do you know if the load is inaccurate or the barrels needs cleaning?
I have about 75 rds through this rifle and I know it is better than I am. I just do not want to waste my time and reloading supplies doing everything wrong.

 

[2Shots]

Re: some range data and a few questions

A couple of questions. I assume you are shooting a .260. And that OAL is a little long unless you're super gluing your bullet to the case mouth. And I am curious what the group size is.

 

[mnhntr]

Re: some range data and a few questions

Sorry the OAL is actually the measurement from the Hornady Comparator so it is not right. Groups are around MOA at 100yds. The best group so far is .75in at 100yds.

 

[Gene Poole]

Re: some range data and a few questions

You have too much spread in your charge weights to be able to find an accuracy node. You're a full grain different with each load. I use 0.2-0.3 grain differences when I work up a load, then fine tune to 0.1 grains to find the center of the node. I never bother with MV; maybe if I had a decent chrono, I could glean something from those data.

Find a node, stick with it, and do more shooting and less calculating.

 

[Break Bad]

Re: some range data and a few questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gene Poole</div><div class="ubbcode-body">... I never bother with MV .... Find a node, stick with it, and do more shooting and less calculating.</div></div>

+1

 

[OneShotJim]

Re: some range data and a few questions

Another +1. I suggest you read up on Optimal Charge Weight (OCW) concepts over in the range report forum where there is a lot of discussion about developing accurate loads using both OCW and ladder tests. You can also read more about OCW at:

http://optimalchargeweight.embarqspace.com/

I do think your chrono velocities will be useful for calculating/estimating your dope once you identify your optimal load.

 

[mnhntr]

Re: some range data and a few questions

thanks