Thread: My 260AI Load Development Begins

Originally Posted by Tikka7mm08

Cool...yep .010 works for me.

Pretty sure 10 thou was all I needed as well but got a bit more in case I ever needed it.

Change of brass brands etc.

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Originally Posted by R93

Pretty sure 10 thou was all I needed as well but got a bit more in case I ever needed it.

Change of brass brands etc.

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How will I know if over-bumping the shoulder? Or will it be so minor it doesn't matter... or do I screw adjust the die until a tight case no longer is and lock it at that setting I guess...

Might be time to invest in a comparator of some sort, or if you are handy with a lathe make something up to fit on your caliper blade. They are a handy way of knowing / measuring what your moving back.

Originally Posted by Tikka7mm08

How will I know if over-bumping the shoulder? Or will it be so minor it doesn't matter... or do I screw adjust the die until a tight case no longer is and lock it at that setting I guess...

If you don't have a gauge - I have a Sinclair 40 degree one - the best way is to remove the striker/firing pin assembly from your bolt and with the bare remainder chamber your cases. This way you can feel the bolt closure against the case without the influence of the main spring. For my target rifles I set the FLS so there is just resistance (need to ensure locking lugs are kept well lubed) as the bolt handle is reaching the bottom of its closing stroke. For field/sporter rifles I set the FLSing so there is no resistance on bolt closing. Need to be careful though you don't over size and create a new problem. If you size a case and it is still too tight, make an adjustment but then use another unsized case to check your adjustment. Don't just keep adjusting and sizing the same case as you will get a nice fit with it but too loose for all subsequent cases sized.

Originally Posted by Tikka7mm08

How will I know if over-bumping the shoulder? Or will it be so minor it doesn't matter... or do I screw adjust the die until a tight case no longer is and lock it at that setting I guess...

I just used an .30 cal collar on an OAL gauge to measure the bump. I don't bother any more.

But yeah, just adjust the die down an 1/8 of a turn until you achieve the desired result. All that you will be missing is the 10 or so thou sizing at the bottom of the case.



Depending on the brass you will get a bit of spring you have to overcome.

You may need a bit more off to give a 1-2 thou bump.


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If you insert your stripped bolt without a case you should feel a wee bit of slack when moving it fwds and backwards off the locking lugs - I like about 4 thou on my custom guns. This wee bit of slack is a guide to how much you have sized, or oversized.

One of most innuendo laced posts I've read on here right to the end with granny sucking.

No: 010 worked but not always so thinking 15 thou of an inch...

Definitely some minimal play with the bolt so guess that is a good thing.

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44gn RL17 140gn VLD. LRABs shoot just under an inch, eldx's slightly better but the VLDs seem to do really well...can someone tell me CTC size of group please??






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This is what I got

Thank you...it is at 101yards if that changes the size?

Originally Posted by Tikka7mm08

Thank you...it is at 101yards if that changes the size?

Changes it to .641 at 101yds mate

I read that RE17 is v.sensitive to seating depth. Loaded up some more Bergers different depths and started with 2.222" (comparator to ogive) just touching. First 3 shots may be the best 100y group I've ever shot. @Dreamer can you pl measure?? Previous best in my laser model 7 in 7mm08 was 0.244 I think. No need to shoot more today as I can't shoot any better with the AMR reticle.

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