Proper Die Setup??

[smoky]

I have a custom built deer rifle (7-08 ackley imp.).  I am finding that some of my hand loads seem to have more resistance to the bolt closing than others.  I have checked the overall length, the ogive length, the case length and all are very close.  I am beginning to think that the difference is somewhere in the shoulder of the case.

I have always set up my dies for a full length resize.  However I was recently told by someone that I should set them up to feel a "bump" at the end of the handle downstroke during the resizing/depriming stage.  Is this true and could this possibly correct what I am feeling when chambering a round.

Actually, I did already adjust the dies as stated above, and when I ran an already once resized case through, it seemed to round off the shoulder, similar to a Weatherby case.  Is this the result of sending an already resized case through again, or is this what happens when you get that "bump" in the down stroke, or could this be something else.

BTW, the dies in question are Redding, but I also use RCBS and Hornady in other calibers.

Thanks for any input


Smoky

[Mikey]

smoky:  I forget the actual technical term for that 'down-stroke bump' you feel when full length sizing a case but if she rounds off the shoulder of your 7mm-08 AI then you most likely have solved your own problem.

When I set a sizing die, regardless of the cartridge or advice to 'neck-size' only, I screw in the die until it touches the shell holder while the ram is in the full upwards postion.  Then, I back off the ram a bit and continue to screw down the sizing die just a bit and bring the ram back up until I feel that 'bump'.  I think it is called a 'de-camming action', but I'm not sure.  Once I get the sizing die/ram into the proper position to make it go 'bump' every time I feel I have the sizing die properly set.  

I used to have a dickens of a time with 308 brass when I reloaded for a Rem 788.  No matter the manufacture, military or civilian, I had to re-size those darn things through 4 different dies before they would chamber properly and allow the bolt to close without undue resistance.  

I have tried neck sizing only but prefer full length.  

Once you have seated your sizing die, check and see if you can full length size a case - sometimes you may have to back off the sizing die just a bit to get that 'bump' but, once you have it set properly she should size your brass so that you do not have any resistance when closing the bolt.  

Hope this helps.  Mikey.

[bigdaddytacp]

I have a custom built deer rifle (7-08 ackley imp.).  I am finding that some of my hand loads seem to have more resistance to the bolt closing than others.  I have checked the overall length, the ogive length, the case length and all are very close.  I am beginning to think that the difference is somewhere in the shoulder of the case.

I have always set up my dies for a full length resize.  However I was recently told by someone that I should set them up to feel a "bump" at the end of the handle downstroke during the resizing/depriming stage.  Is this true and could this possibly correct what I am feeling when chambering a round.

Actually, I did already adjust the dies as stated above, and when I ran an already once resized case through, it seemed to round off the shoulder, similar to a Weatherby case.  Is this the result of sending an already resized case through again, or is this what happens when you get that "bump" in the down stroke, or could this be something else.

BTW, the dies in question are Redding, but I also use RCBS and Hornady in other calibers.

Thanks for any input


Smoky

......I prefer to have the ram "cam over" on dies set for full length sizing.....BUT with a custom chamber and off the shelf dies you might have a difference in specs and the only way around that is to send 3 fired well formed cases and have a die cut for your chamber.....Redding dies are well made and work well but they have no control over your guns chamber when it has been custom cut........also I would do a chamber cast to find the actual neck diameter and chamber specs. .......make sure the shell holder is flat on top and is the correct thickness ....sometimes they can be too thick or out of sinc with the dies and press ram.....HTH.good luck and good shooting-loading!!

[John Traveler]

The difficulty you guys are describing is pretty common for  bottle-necked cartridges with a minimum body taper.  This would include most of the Ackley Improved series, and the ones based on the .308 Winchester parent case.

You can NOT sucessfully "partially resize" cases such as the .308 Winchester, .243, .284 Wincheser, etc using standard full-length dies  because partially squeezing down the body of the case actually elongates the head-to-should cone dimension.  The result is difficult or often, impossible chambering.

In those minimum-taper bottlenecked cases, and using a full-length resize die, you must FULL-LENGTH resize completely.  That final "BUMP" assures that the head-to-shoulder cone dimension is restored so that easy chambering is possible.

Neck sizing only is done on these cases using specially-cut dizes that do NOT subsequently elongate the head-to-should cone dimension.

HTH
John

[Jack Crevalle]

I may be missing something here but why don't you just try to close the bolt on a resized case before you seat a bullet or primer? If it closes easy then you take can rule out resizing and revisit ogive and OAL. Trim length might still enter into it though, also.

[Dave in WV]

Another thing to consider is neck wall thickness since it's a custom chambering. The neck area in the chamber could be a little tight and outside neck reaming could cure the tightness.  Dave