RCBS Full Length Resizing Die Modifications

[RonAKA]

I just purchased a set of RCBS dies for a upcoming 6.5 Remington Magnum build. It is just the standard FL die and bullet seater. Now that I have them and have measured up the FL die I am having some misgivings about them - not that I have a lot of choices however.

The first issue is that the expander ball measures at 0.2616". I think that is too small and will result in excessive neck tension. The second is that it appears the neck is too small. The new unprimed brass I have seems to be small in the neck already, and is 0.292" OD. It will will not fit in the die.

My concern is that with an neck that is too small I am going to be overworking the brass in the neck, big time. And when the ball does not open it up, I will have excessive tension.

So my questions: Has anyone switched out the expander ball and tried to customize the diameter? I was considering getting an expander intended for a .270 and then turning down the ball to about 0.2635. And on the neck in the die, Forster offers a service to custom size them. But, I don't think they will do a RCBS die. Has anyone tried to hone out their die neck using something like a valve stem guide flexible hone? I believe Flex-Hone makes them, and an 8 mm one may do the trick.

 

[jepp2]

Has anyone tried to hone out their die neck

I routinely hone my die necks to get them the diameter I want. As you stated, most come undersize to make sure they will properly size all brass. This can result in seriously undersizing the neck on most brass, then the expander must open them back up. I tried flex hones without success. What I found that works extremely well are the laps I get from MSC. http://www.mscdirect.com/browse/tn/Abrasives/Laps-Hones/Laps/Through-Hole-Laps?navid=12100079

I hone the die necks for 2 reasons. First is to reduce the extra work on the neck. But mostly I do it to keep my necks as straight as possible. The less the expander has to do, the less the risk of pulling the neck off center. (I also set my expander so it exits the case neck as soon as start to lower the press handle). This way the case is better supported by the die. I routinely achieve TIR of less than 0.001" with my setup.

 

[MagnumManiac]

First off, the expander is easy to modify, chuck it up in a lathe, or a drill press, take some 600 wet/dry and spin it up and take some metal off until you get .261"/.2615", or more if you want LESS neck tension. Use plenty of WD-40 or similar to keep the paper wet. Your expander at .2616" is only .0024" smaller than bullet diameter, you could call RCBS and tell them you want one .262" or larger, they will send it to you free of charge.
Secondly, I have several dies, not just RCBS, that have a minimum 'feel' as the neck passes through the die, they must be doing something, cause the neck is still being expanded as it is withdrawn over the ball. This is a good thing, the brass isn't being overworked this way.
Honing ENLARGES the neck, if your necks are already loose, they will get looser if you hone the neck of the die.
Lastly, without ACTUALLY measuring a fired case, one that has been sized, and one that has been sized and passed over the expander, you just don't know what the differences in the neck are going to be.
My 264WM Winchester brass measures like this, fired .2962", sized without expander, .2899", with expander .2923". My expander is modified to be .2625" and is highly polished. I also have another for Rem brass that is .2615", it likes a little more tension due to differing alloy ratio.
My comp rifle, I have a hunting rifle too, gets a bushing sizing at exactly .292", so this is on the money for a .0015" tension.
.2635" is too large, this will only give you .0005" tension, and, if you use some bullet brands that are .263" in diameter, they will be loose in the neck.

Cheers.

 

[ireload2]

You can buy oversize expanders for Forster dies and install the Forster stem in the RCBS die.

I would recommend that you buy a set of .0251 to .500 minus .0002 gauge pins and if you can spare a little more cash a set of .061 to .250 gauge pins.

Anyone can lap out a die neck. Here is a guy that will show you how to do it.
https://rickaverill.com/projects-past-and-present/lapping-reloading-dies/
https://rickaverill.com/projects-past-and-present/lapping-reloading-dies/

 

[RonAKA]

I routinely hone my die necks to get them the diameter I want. As you stated, most come undersize to make sure they will properly size all brass. This can result in seriously undersizing the neck on most brass, then the expander must open them back up. I tried flex hones without success. What I found that works extremely well are the laps I get from MSC. http://www.mscdirect.com/browse/tn/Abrasives/Laps-Hones/Laps/Through-Hole-Laps?navid=12100079

I hone the die necks for 2 reasons. First is to reduce the extra work on the neck. But mostly I do it to keep my necks as straight as possible. The less the expander has to do, the less the risk of pulling the neck off center. (I also set my expander so it exits the case neck as soon as start to lower the press handle). This way the case is better supported by the die. I routinely achieve TIR of less than 0.001" with my setup.

Thank you. That is one of the most informative responses to a post that I have ever gotten. It is exactly what I am looking for. I had never heard of through-hole laps before, and with their 15% adjustment range, they should be just the ticket! Your reasons for doing it are exactly the same as mine.

 

[RonAKA]

First off, the expander is easy to modify, chuck it up in a lathe, or a drill press, take some 600 wet/dry and spin it up and take some metal off until you get .261"/.2615", or more if you want LESS neck tension. Use plenty of WD-40 or similar to keep the paper wet. Your expander at .2616" is only .0024" smaller than bullet diameter, you could call RCBS and tell them you want one .262" or larger, they will send it to you free of charge.
Secondly, I have several dies, not just RCBS, that have a minimum 'feel' as the neck passes through the die, they must be doing something, cause the neck is still being expanded as it is withdrawn over the ball. This is a good thing, the brass isn't being overworked this way.
Honing ENLARGES the neck, if your necks are already loose, they will get looser if you hone the neck of the die.
Lastly, without ACTUALLY measuring a fired case, one that has been sized, and one that has been sized and passed over the expander, you just don't know what the differences in the neck are going to be.
My 264WM Winchester brass measures like this, fired .2962", sized without expander, .2899", with expander .2923". My expander is modified to be .2625" and is highly polished. I also have another for Rem brass that is .2615", it likes a little more tension due to differing alloy ratio.
My comp rifle, I have a hunting rifle too, gets a bushing sizing at exactly .292", so this is on the money for a .0015" tension.
.2635" is too large, this will only give you .0005" tension, and, if you use some bullet brands that are .263" in diameter, they will be loose in the neck.

Thank you for the very informative post. Spinning it and taking the metal down with wet/dry is what I kind of planned by default. Good to hear it is reasonable to do. I user a Forster Bushing Bump sizer die for my 6BR. Forster uses an expander ball that is 0.001" smaller than the nominal caliber, with the theory that your brass springs back 0.001" plus the 0.001" undersize ball, for a total fit on the bullet of 0.002". It works quite well for me. I just measured the ball in my 6BR die and found it was 0.2423", so really 0.0007" under. I will target to be a full 0.001" under.

 

[dkhunt14]

In a lot of my guns more tension and as much as .005 gives better 1000 yard accuracy. Brass never spring back the same. It depends on softness. The more you shoot them without annealing the more they spring back. Matt

 

[RonAKA]

You can buy oversize expanders for Forster dies and install the Forster stem in the RCBS die.

I would recommend that you buy a set of .0251 to .500 minus .0002 gauge pins and if you can spare a little more cash a set of .061 to .250 gauge pins.

Anyone can lap out a die neck. Here is a guy that will show you how to do it.
https://rickaverill.com/projects-past-and-present/lapping-reloading-dies/

Installing Forster expanders would be my easy first choice. However, I checked my 6BR Forster Bushing Bump Sizing Die and the threads look way smaller than the RCBS on the internal parts. The thread for the whole assembly where it fits into the die body is much larger on the Forster Bushing die. That may be because of the bushing design. If I was to use a Forster assembly it would have to be smaller than what I have on my bushing die. I measure the RCBS assembly to body thread as 7/16x20 tpi. In the photos the assembly does look smaller for the standard non bushing die. I guess I would have to find out if that thread is the same as the RCBS. Forster do not produce a 6.5 RM die, but I would think the internal assembly for a 6.5x284 should work. That is a good option I will have to investigate.

Gauge pins also seem to be a very good idea for honing the neck. I was planning to try and find a metric or letter drill that was real close. Thanks for the procedure link as well. Good stuff. This is all looking very doable, one way or another...

 

[RonAKA]

In a lot of my guns more tension and as much as .005 gives better 1000 yard accuracy. Brass never spring back the same. It depends on softness. The more you shoot them without annealing the more they spring back. Matt

Yes, that is a consideration. I have essentially one set of brass for this gun, and I need to make it last the lifetime of this gun ideally. That is why I wanted to go easy on the neck dimension cycling. When I bought bushings for my 6BR I got two sizes based on that thinking. So far with Lapua brass and 5 firings I have not had to resort to changing bushing to compensate for increased springback.

Yes, light neck tension does have some disadvantages. I once chambered a bullet that had a significant jam, and for reasons I don't recall, tried to extract it unfired. Ouch, powder everywhere, that was impossible to fully clean out at the range. Trip home without much shooting done!

 

[dkhunt14]

Wow that depends on many pieces is in that set. If it is only 20 pieces, you are talking about possibly 100 firings. I like new brass for my 1000 yard BR shooting, it seems after 15 or so firings it is not quite as accurate anymore. I also anneal to keep them soft. I look at brass at the price, as an expendable item. I figure if I get 10 or more fairings it paid for itself. Of coarse I am looking for great winning accuracy. Matt

 

[ireload2]

Before Bonanza was bought by Forster they produced die sets in 6.5 Rem Mag. If you have a lot of patience you might find one of these die sets. I bought a number of the Bonanza 6.5 Rem Mag Benchrest Seating dies to modify to other calibers. Somewhere out there is a Bonanza FL 6.5 Rem Mag die set. In the old days Bonanza would provide you with 6.5 Jap and 7.7 Jap BR seaters too.
You might have to swap expander decapper bushings around to get the right internal thread with the right external thread. If nothing works out a good quality cap screw can be drill and tapped in a lathe to make a nice bushing.

I just noticed a standard set of Bonanza 6.5 Rem mag dies on ebay. They do not have the good BR seater and they are way over priced. But the die sets are out there if you have the patience to find them.

Installing Forster expanders would be my easy first choice. However, I checked my 6BR Forster Bushing Bump Sizing Die and the threads look way smaller than the RCBS on the internal parts. The thread for the whole assembly where it fits into the die body is much larger on the Forster Bushing die. That may be because of the bushing design. If I was to use a Forster assembly it would have to be smaller than what I have on my bushing die. I measure the RCBS assembly to body thread as 7/16x20 tpi. In the photos the assembly does look smaller for the standard non bushing die. I guess I would have to find out if that thread is the same as the RCBS. Forster do not produce a 6.5 RM die, but I would think the internal assembly for a 6.5x284 should work. That is a good option I will have to investigate.

Gauge pins also seem to be a very good idea for honing the neck. I was planning to try and find a metric or letter drill that was real close. Thanks for the procedure link as well. Good stuff. This is all looking very doable, one way or another...

 

[RonAKA]

Wow that depends on many pieces is in that set. If it is only 20 pieces, you are talking about possibly 100 firings. I like new brass for my 1000 yard BR shooting, it seems after 15 or so firings it is not quite as accurate anymore. I also anneal to keep them soft. I look at brass at the price, as an expendable item. I figure if I get 10 or more fairings it paid for itself. Of coarse I am looking for great winning accuracy. Matt

I have 150 cases of Remington brass. Not my first choice, but my only choice. 6.5 RM is becoming as rare as hen's teeth. On my .264 WM I have gotten up to 20 firings per case. If I get that, my barrel will be burned by then anyway! I will anneal every 5 firings to preserve the brass. Believe it or not I have gotten up to 20 on the .264 Winchester brass with no annealing. They always died with a longitudinal crack in the neck. I'm much more careful than I was as a kid!! I bought my first rifle, a .264 WM in 1965 or so. It was a hot item back then.

 

[RonAKA]

I would recommend that you buy a set of .0251 to .500 minus .0002 gauge pins and if you can spare a little more cash a set of .061 to .250 gauge pins.

Have not had luck so far in finding reasonably priced gauge pins. However, I have a couple of 19/64 drill bits that I think I will lap the shanks with wet/dry down a bit, and they should work for gauge pins to monitor my progress in lapping the die neck.

It appears my R-P brass has a fairly consistent, but thick neck thickness of 0.016". That means a loaded neck diameter of 0.296". With a 0.002" targeted fit on the bullet, and allowing for a .001 springback, that means I need a neck in the die of 0.293" or 0.292 if I want to bring that last 0.001" up with an expander ball-my preferred practice.

Things are starting to come together. I think I have a source of through-hole laps in Canada and will order one. Is there a recommended lapping compound abrasive size? I need some to lap my bolt lugs too and perhaps I can use the same for both...

 

[ireload2]

Vermont gage will sell individual gage pins at about $3.00 each
If you have a micrometer you can also use a small hole gauge.
I use both
I think you can get a full set of Chinese made pins from .251 to .500 Minus .0002 for about $88 plus shipping.
I trolled there about a month and got a set of used pins for $47 plus shipping.
280 to 320 silicon carbide used with oil should work ok.

Have not had luck so far in finding reasonably priced gauge pins. However, I have a couple of 19/64 drill bits that I think I will lap the shanks with wet/dry down a bit, and they should work for gauge pins to monitor my progress in lapping the die neck.

It appears my R-P brass has a fairly consistent, but thick neck thickness of 0.016". That means a loaded neck diameter of 0.296". With a 0.002" targeted fit on the bullet, and allowing for a .001 springback, that means I need a neck in the die of 0.293" or 0.292 if I want to bring that last 0.001" up with an expander ball-my preferred practice.

Things are starting to come together. I think I have a source of through-hole laps in Canada and will order one. Is there a recommended lapping compound abrasive size? I need some to lap my bolt lugs too and perhaps I can use the same for both...

 

[RonAKA]

You can buy oversize expanders for Forster dies and install the Forster stem in the RCBS die.

BINGO! Just got off the phone from Forster and their Canadian supplier. I have a Forster 6.5x284 expander assembly on order. By all accounts it should work fine. Forster use 7/16x20 threads in their standard full length dies, the same as RCBS. It comes with a 0.263 expander ball which should be fine.

 

[jepp2]

Is there a recommended lapping compound abrasive size?

I have a kit similar to this one offered by Brownells: http://www.brownells.com/gunsmith-t...ilicon-carbide-abrasive-kit-prod977.aspx#Sale

I start with the 240 grit and when I get close I go to 400 then 600. I always polish the inside of the die body including the neck with Flitz then Mothers Mag polish. I find it reduces the effort to FL size substantially. I do have the pin gage set, but I also size brass and use a good 0.0001" accuracy micrometer to check the neck OD to check my progress. Doesn't hurt to stop early. You can't add material back. You can always take some more off.

Not probably needed, but I wrap the shaft of the lap with black electrical tape to nearly the same diameter as the die body. I lightly oil the tape, as this makes sure I keep the lap centered in the die.

 

[BountyHunter]

Once you get your gun, fire some brass 3x and send it to JLC Precision, Jim Carstenson with a Redding body die. For $80 he will take the body die, convert it to FL bushings and custom hone it for your chamber. Turn around is 2-3 weeks.

 

[RonAKA]

I have a kit similar to this one offered by Brownells: http://www.brownells.com/gunsmith-t...ilicon-carbide-abrasive-kit-prod977.aspx#Sale

I start with the 240 grit and when I get close I go to 400 then 600. I always polish the inside of the die body including the neck with Flitz then Mothers Mag polish. I find it reduces the effort to FL size substantially. I do have the pin gage set, but I also size brass and use a good 0.0001" accuracy micrometer to check the neck OD to check my progress. Doesn't hurt to stop early. You can't add material back. You can always take some more off.

Not probably needed, but I wrap the shaft of the lap with black electrical tape to nearly the same diameter as the die body. I lightly oil the tape, as this makes sure I keep the lap centered in the die.

The place I will likely buy the through hole lap from has a minimum order. They have this diamond lapping compound. It is rated at 36-54 microns, which I believe converts to about 500 to 300 grit. Do you think it will work? I would like to lap my bolt lugs with it too...

On the electrical tape trick, I gather you lap from the inlet end of the die then, and bump the diameter up to cartridge size?

 

[RonAKA]

Once you get your gun, fire some brass 3x and send it to JLC Precision, Jim Carstenson with a Redding body die. For $80 he will take the body die, convert it to FL bushings and custom hone it for your chamber. Turn around is 2-3 weeks.

Unfortunately, I am in Canada, and doing stuff like that across the border tends to be painful and expensive.

 

[ireload2]

Gesswein is another source for professional quality stones and other abrasives.
People that make plastic injection molds use Gesswein tools and abrasives.
http://www.gesswein.com/?gclid=CjwK...jDHtMBpNyQmYxidU3_spyHUXWQeCs5UBQOhoCnFrw_wcB
http://www.gesswein.com/?gclid=CjwK...jDHtMBpNyQmYxidU3_spyHUXWQeCs5UBQOhoCnFrw_wcB