RCBS (or similar) GMM seating die for the 6.5 Grendel?

[hcb]

Hey, all, I shoot a fair number of 6.5 Grendel rounds each month (100-200) from an AR-15 for hunting. I'm happy if I get 1 MOA from my loads/rifle. That said to say: I'm not looking for crazy accuracy/perfection from my loads. I use an AP press and a powder drop and crank them out. I'm using Lee dies and they work fine. But, back when I was on crack and using the .224 Valkyrie, I had a set of RCBS Gold Medal Match (IIRC the name) dies and the bullet seater had a window in the side to allow the bullets to be dropped in from the top instead of being seated into case mouth by hand and then shoved up into the seater die with the ram. I really liked that feature and I find that my biggest hold up on loading these rounds for the 6.5G is setting those bullets on the case mouth. Compounding the problem is that, due to projectile scarcity, I have also started using a different bullet than my normal bullet and they tend to tip more easily and, therefore, are prone to falling out or getting badly misaligned and missing the opening in the seating die when the AP press indexes.

Is there one of the RCBS (or any other seating die which has this "top load" feature) seating dies which could be used for the 6.5G? I have zero knowledge of how the seating die actually centers up on the cartridge to seat the bullet straight but I'm pretty sure it's not on the body of the cartridge (like a full-length resizing die). I *assume* it centers up on the neck but maybe it's on the shoulder. So, I'm here to ask: has anyone used, even if they had to modify it, another top-load seating die for the 6.5G? I have a lathe and am fairly adept at using it: if the body of the die needed to be cut down I could do that. I suppose, if the seating die worked off the shoulder of the cartridge, I could get one in that caliber and then ream it with a 6.5G reamer but I don't have a 6.5G reamer on hand.

Anyway, thanks for your time.

--HC

[Harpoon1]

https://www.frankfordarsenal.com/reloading-tools/presses-and-tools/dies/universal-bullet-seating-die/1116715.html

And most seating dies DO use the body of the case to center up on the seating stem.

[hcb]

Thank you for the reply. I've ordered a set. Will be here Wednesday.

As for centering, I guess I never paid much attention to how far into the die body the case goes. I should pay more attention.

Thanks again. It'll be interesting to see how well it works.

--HC

[hcb]

I got the set and finally about 2 weeks ago tried it out. Overall it's good. The downside is that on the short Grendel cases, I have to use the longest seater and then set the die at the lowest setting to get to the seating depth I need. This means the seating stem is partially blocking the bullet entrance window. It's a tight fit, I have to squeeze the bullet past the seating stem. I'm going to fix this problem mostly by using a Dremel to open up the relief at the bottom of the window to allow more room for the bullet to drop in. I've not given much serious thought to doing it or if it will work but I may need to shorten the body of the die, or otherwise do some machining on the die to make it work better for the sort case of the Grendel. However, it does give me what I wanted in that I can now drop a bullet in from the top/side instead of into the case mouth.

Thank you for the suggestion.

--HC

[Happy2Shoot]

... tip more easily and, therefore, are prone to falling out or getting badly misaligned and missing the opening in the seating die when the AP press indexes.

...
Anyway, thanks for your time.

--HC

You need an "M-die". I think the "M" stands for mandrel.

I bought 2 to make what I needed.

lyman 30 short 7349003 and 260 rem 7349052.

I assume you could hacksaw the 260 rem down to fit the 6.5 grendel

The M-die opens the case mouth just a little, to hold the bullet perfectly.

I also really like these dies with the bullet seating sleeves.

Redding Competition Seater Die
413448.jpg

Hornady Custom Grade New Dimension Bullet Seater Die

[Mad Charlie]

There are a few other combo's of lyman part #'s that will work. As a matter of fact I ordered some on 3/2/21. After not having seen any charge to my bank account, or confirmation e-mail, I called to see what was up. I was informed that they neglected to tell me that shipping was 6-8 weeks away. I think that it is time to fire up the old Monarch and make my own stuff, to my exact spec's.

I can do it better anyway, but they were cheeper than my time.

[Happy2Shoot]

Let me know if you need measurements

[Mad Charlie]

Let me know if you need measurements

Thanks, my design will be a one piece stem and plug dimensioned to give me less neck expansion than the average expander ball
and I can single point the thread fit much tighter than most dies. A kiss of crimp with my taper crimp die will smooth out the M step if necessary.

There have been reports of the Lyman plug unscrewing from the stem in use unless Locktite is used, one piece stem/plug will alleviate that issue.

Will see how it goes.

[Happy2Shoot]

Here is a link about the M-Die.

https://www.ar15.com/forums/Armory/Educate-Me-on-Lyman-M-Dies/42-452183/?page=1

[Oryx]

trick to the M-die is very small adjustments so you don't over flare.
I started using the M-die when I stared casting and it helped tremendously in the seating operation. If using with jacketed bullets only the slightest kiss is what you want (if at all). I just use a regular mandrel instead with the jacketed bullets - better precision grinds and can do the whole neck in steps rather than just flare the mouth.