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Topic: Seating depth testing (Read 175 times) previous topic - next topic

Seating depth testing

I post this as a good demonstration on how seating depth testing is arguably as, if not more, important as proper charge weight.  I had muffed up a distance to lands measurement and had been shooting matches at 600 and 1000yds with a much less than optimal seating depth.  I had extensive course and fine powder charge tests on this bullet/case using a couple of known good powders for the cartridge but still I was getting erratic results; sometime great, sometimes average.  I remeasured my distance to lands after finding my problem with the previous measurement and ran through a test of 0.010, 0.013, 0.016 and 0.019" off light touch (I started at '10 off' as the Berger 184 hybrid is known to shoot well near 0.015" in most guns).  Here are the results:

0.010" off



0.013" off



0.016" off



0.019" off



You can see how, when you get close and you in the powder charge ball park the groups go horizontal with low vertical.  Once in the optimum seating depth it pulls together.  These were shot at 300yds.

Robin



 

Re: Seating depth testing

Reply #1
I couldn't agree more about seating depth being more important than charge weight once you're close.

I split between +.004 & +.005 out in MN last weekend making + .0045 my targeted seating depth. I really wanted to seat at .004 but had never shot +.003 on the new Lilja barrel before and was worried it was too close to the lands or on the edge of the node and didn't want to risk it coming out of the seating tune.

I'll be looking for scores on AS this weekend! I wanted to be in Harris MN shooting one more 600 yard match before Nationals but had business today I couldn't ignore.
Dave

Re: Seating depth testing

Reply #2
IBS Nats Dave?  Where are they this year?


Re: Seating depth testing

Reply #4
I suppose that is not too far of a drive for you.  Would that be your 'home range' if you have such a thing considering your location?

Re: Seating depth testing

Reply #5
I suppose that is not too far of a drive for you.  Would that be your 'home range' if you have such a thing considering your location?

Has to be 7 hours to Harris from home, 9 hours from my place up north according to Google

I've never been to Harris before. Elbow Lake MN last week is closer. Hunter's point in Hartford SD is about 6 hours from my home but I've never been there either. All 600 yard venues but they're trying to expand to 1000 at Elbow Lake.
Dave

Re: Seating depth testing

Reply #6
I guess I've got it good; I have 3 1000yd ranges within 4 hrs (closest 2.5hrs) and 3 600yd ranges within 3 hrs..  I need to stop complaining about the 3 hr runs :-[ .

Re: Seating depth testing

Reply #7
I would imagine Eric shoots at most of the Minnesota ranges.