Thread: My 260AI Load Development Begins

Cool...yep .010 works for me.

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 Tikka7mm08

Yes it feels like on some cases the FL dies just isn't 'reaching' the shoulders well enough...and have the shell holder hitting the base quite firmly on the cam over of the press.

Yeah, if your die is only sizing the body and not quite reaching the shoulder what will happen is the shoulder will actually move fwd and the situation is made worse. The best analogy is if you wrap your fingers around a peeled banana (no crude comments required) and put your other hand hard (shit another opening) against the hand holding the banana and then squeeze. Some banana will obviously ooze out around your fingers but most of it will go up. This is what happens when you only partially FLS and squeeze the body and don't contact the shoulder.

Please excuse if I appear to be teaching granny to suck eggs.

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

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.

Originally Posted by Tikka7mm08

Righto... how much ground off the FL die?

How thick was the feeler gauge you placed under the case? I would go that much as a minimum for material removal. That way when the shell holder contacts the die body it should be the right amount of bump.


Soz, I see it's already been answered by R93

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