Shoulder bump set up on Forster Co-Ax, and a few other questions.

[OzzyO20]

I'm very new to reloading, and I've tried to research this but still have a few questions. Please bear with me.

1. I have a Forster co-ax I got for a song off a buddy who's taking some considerable time off from shooting. I also have the Redding 6.5 CM Competition die set with body die, bushing die, and micrometer seating die. At the advice of some members here, and in doing research I also bought a Redding full length S type bushing die. From what I read, I'm looking for .002 - .0015" bump in the shoulder, but most everything I read involved shell holders that adjust incrementally to aid in setting this. Obviously the co-ax does not have this feature (but it is an option to convert to that I'm not opposed to necessarily). Do I pull the handle all the way down and thread the FL S type die down until it contacts the s-jaws, then start turning it in or out until I get the desired set back? This seems pretty difficult and tedious to do in the thousands of a inch. The good news though is I'm loading for one gun with the dies so once they're set I can just leave them (I think?) and not worry.

2. I have a Hornady comparator gauge. I understand its supposed to measure the datum line of the shoulder, and I take a once fired case and subtract the .002 or .0015" to find my target length. My question here is does the resizing and or firing change where it measures from? Is there a better way to measure headspace or will this suffice? Just want to make sure everything is consistent and safe on this critical measurement.

3. On the new Redding FL type s die, it came with what looks like a silver expander and a second smaller black mandrel to hold the decapping pins. I'm using a Redding universal to decap, so I wont be installing a decapping pin, but what do I do with the rest of the components? The gentleman on the Panhandle Precision channel on YouTube just scrapped it all and threw the busing in the cavity and turned it down and backed it off a tad so it would float. Is this acceptable, or should I leave the stem in with the smaller mandrel and just not install a decapping pin?

4. I'm going do start with 100 pieces of once fired Prime brass that I shot out of my AI I'm loading for, but I got 200 pieces of once fired Lapua 6.5 CM in the deal as well. 100 fired from his Surgeon and 100 fired from my old custom R700. I know they were only fired once, so I'm not worried there, but my question is will my die settings change with different brass? I have a few different bushings because I know Lapua is a bit thicker and my neck bushing will change, but will the bump setting change as well?

I know this was a long winded post, and I appreciate the help in advance. I'm sure you guys will see more from me when I actually start, just trying to wrap my mind around it before I get going. Waiting on an inline fabrications mount for the coax so it'll fit better on my work bench.

Thanks guys,

Ryan.

 

[PinesAndProjectiles]

1. Start shallow and slowly run the die deeper until you reach .001-.002 of shoulder bump.
2. No. The Hornady comparator will work just fine. Use the comparator on your fired brass and find out what the average length is. Subtract .001 or .002 from this measurement and this is what you want to shoot for.
3. Remove the decapping pin and/or the decapping pin collet. If you decap in a different step, it isn't needed. You may want to remove the expander altogether as using it defeats the purpose of using the bushing. When you push the brass up into the die, the neck will get sized down from the die, and when you pull the brass back down, the expander will change your neck dimensions.
4. The die settings may change, but shouldn't. I would size them all the same, then fire them from your rifle as they are then "fireformed" to your chamber.

 

[kthomas]

Here's a tool made from Whidden that is a very quick reference to how much your are bumping the shoulder back. Rather than doing mental math, you have a simple visual indicator for how much the shoulder was bumped back:

https://www.whiddengunworks.com/product/case-gauge-3/

I have one for my 6.5 creedmoor and love it. Measuring with a Hornady case comparator works great as well (I own one), but if I'm reloading 6.5 creedmoor, I'm always reaching for this Whidden Case Gauge.

 

[spife7980]

Mulisha summed it up nicely but I have my comments below in red.

I'm very new to reloading, and I've tried to research this but still have a few questions. Please bear with me.

1. I have a Forster co-ax I got for a song off a buddy who's taking some considerable time off from shooting. I also have the Redding 6.5 CM Competition die set with body die, bushing die, and micrometer seating die. At the advice of some members here, and in doing research I also bought a Redding full length S type bushing die. From what I read, I'm looking for .002 - .0015" bump in the shoulder, but most everything I read involved shell holders that adjust incrementally to aid in setting this. Obviously the co-ax does not have this feature (but it is an option to convert to that I'm not opposed to necessarily). Do I pull the handle all the way down and thread the FL S type die down until it contacts the s-jaws, then start turning it in or out until I get the desired set back? This seems pretty difficult and tedious to do in the thousands of a inch. The good news though is I'm loading for one gun with the dies so once they're set I can just leave them (I think?) and not worry.

You can screw it down to touch but I would do like mulisha said and start further back and work down.
Screw it all the way in and then out half a turn, probably pretty much like the instructions say to and then go from there. To actually adjust it youll just loosen the lock ring screw, turn the die in a little deeper, tighten the lock ring back up and then size. If it sizes too much back it out, if it doesnt size it enough screw it in deeper. Small movements make a big difference when were looking at thousandths of an inch.

2. I have a Hornady comparator gauge. I understand its supposed to measure the datum line of the shoulder, and I take a once fired case and subtract the .002 or .0015" to find my target length. My question here is does the resizing and or firing change where it measures from? Is there a better way to measure headspace or will this suffice? Just want to make sure everything is consistent and safe on this critical measurement.

No, firing wont change the dimension you use to measure. For a 6.5 creed you will use either the C .375 or D .400 inserts. The means the circle it touches the case with is .375/.400" in diameter. It allows you to measure from a point on the shoulder to the case head consistently. Trying to use bare calipers would inevitably measure from a different point on the shoulder each time. Using a datum makes that measurement repeatable.

3. On the new Redding FL type s die, it came with what looks like a silver expander and a second smaller black mandrel to hold the decapping pins. I'm using a Redding universal to decap, so I wont be installing a decapping pin, but what do I do with the rest of the components? The gentleman on the Panhandle Precision channel on YouTube just scrapped it all and threw the busing in the cavity and turned it down and backed it off a tad so it would float. Is this acceptable, or should I leave the stem in with the smaller mandrel and just not install a decapping pin?

You can leave the decapping pin in, I do. If its not pushing out a primer its just floating in space and not really hurting anything.

What you do depends on what bushings you get and what your goals are. Measure a loaded rounds neck diameter. For a 6.5 creed example lets assume that it measures .292 (.264 bullet diameter plus .014 of brass thickness for each side of the round .264+.014+.014=.292)

Generally people select a bushing .002" under the loaded round diameter. If you got a bushing that was .290 (.002 less than loaded round) then you could just do that to size your necks back down and not have any expansion step necessary. What that would do is push any neck thickness irregularities to the inside of the brass leading to inconsistent neck tension. Lapua brass is pretty consistent so you could do that is you wanted to with minimal compromise. Many brass samples will have a couple thousandths of difference in the thickness of the necks from one side of the brass to the other.

If you wanted to push those irregularities in neck thickness to the outside and create a perfectly round inside of the neck touching the bullet you would need to either 1)turn your necks to shave the irregularities off (yuck) or you would need to 2) expand it from the inside so that they get pressed outwards. This can be accomplished by the expander ball or a separate expanding mandrel step.

In order to expand though it would need to be sized down smaller in order to then get opened up larger. Using a .289 or .288 bushing would size the round down .004 under the loaded round diameter but it would also allow the expander to open it back up. If you ran an expander after the .290 bushing it wouldnt really do much of anything and just sort of slide through freely. The expander should measure right around .262 (.002 less than a bullets diameter)

In either case you want to have the type s bushing float just a tad. If its tight in there it could be a little cockeyed and thus make your necks a bit cockeyed. Tighten it down to right before it stops rattling.



4. I'm going do start with 100 pieces of once fired Prime brass that I shot out of my AI I'm loading for, but I got 200 pieces of once fired Lapua 6.5 CM in the deal as well. 100 fired from his Surgeon and 100 fired from my old custom R700. I know they were only fired once, so I'm not worried there, but my question is will my die settings change with different brass? I have a few different bushings because I know Lapua is a bit thicker and my neck bushing will change, but will the bump setting change as well?

The settings can vary a bit depending on the brass thickness, its work hardening, its actual dimensions of the chambers it was fired in etc.
It wont vary a whole bunch, but it is worth paying attention to what the different brands, and even lots and number of firings actually measure.

I know this was a long winded post, and I appreciate the help in advance. I'm sure you guys will see more from me when I actually start, just trying to wrap my mind around it before I get going. Waiting on an inline fabrications mount for the coax so it'll fit better on my work bench.

Hope my long winded answers help

Thanks guys,

Ryan.

 

[OzzyO20]

Thank you guys, this has seriously cleared a few things up in my mind. I did sit down last night and take begin to take an average of case growth to find out my target resized length. I stopped at 15 cases because all but 1 case were identical, and the one oddball was only .0005 difference. I was measuring once fired Prime 130 6.5 CM with a Hornady .375 comparator on a set of Mitutoyo calipers. I took a loaded round and measured it with the same tools, and I came up with .0055 difference (1.5565 fired minus 1.5510 new), does that seem excessive to anyone else? I tried to look up SAMI spec, but couldn't get the figures from a .375 datum line on google and was admittedly getting pretty sleepy so I went to bed.

 

[spife7980]

No, not unusual from factory to fired. 5 thousandths of growth is just fine. Some combinations, usually the cheapest ammo, grows twice that. Plus, the accuracy international chambers are something like .006 over go gauge or something, an extra .002 to make sure factory ammo always chambers.
Just size them back to 1.555 and you should be good. .0015 clearance is just about perfect imo.