Suggestions for the Dillon RT1200

[Raydee38]

I finally broke down after years of hand trimming 223 and bought the Dillon rapid trimmer. Now I have a question about the setup.

I see that the 1200 is also a resize die so my plan is just to setup a separate tool head with a decapper and then the trimmer. Can I use my current sizing/decapping die and just back the die out of the head so that it only decaps and does not resize? I was told not to resize first as the brass may spin in the trimmer. What do you guys think?

[RDA]

I finally broke down after years of hand trimming 223 and bought the Dillon rapid trimmer. Now I have a question about the setup.

I see that the 1200 is also a resize die so my plan is just to setup a separate tool head with a decapper and then the trimmer. Can I use my current sizing/decapping die and just back the die out of the head so that it only decaps and does not resize? I was told not to resize first as the brass may spin in the trimmer. What do you guys think?

You can do that (back off sizing die) or you can buy a cheap Lee decapping die (this is what I use). I also have tried using the sizing/decapping die set at about 50% of the resizing and then let the sizing/trim die to finish the job.

[rjacobs]

just get a lee and be done. they are 12 bucks last time I bought one, might be 15 now.

And if you use your trim die as your only source of sizing you need to expand the neck afterwords with something like a mandrel die. I suggest the 21st Century Shooting expanding dies for no other reason in that they are fairly inexpensive(you buy one body and you can buy multiple expander mandrels for various calibers) and they work great.

[Raydee38]

What I do now is use a Lyman case prep station and debur and chamfer the cases after they are sized. Can I still do that?

[RiggerJJ]

You do not need to expand the neck after the 1200, just a slight mouth expansion will work fine. The neck tension you get from the 1200 trim die is quite a bit, however I think it is good to have that much for AR15s. I would not do any sizing operation including neck sizing after the 1200 trim die, may get inconsistent lengths...
jmho

I use a slight mouth expansion to seat the bullet easily, and close it with a light crimp after seating for both 223 and 308 3gun ammo. 1/2 to 3/4 moa. And the best thing is I don't have to handle each case, I do not de-bur or chamfer. Just run the brass thru a processing head with Dillon trimmer, then load it.
jj

[gigs]

Keep in mind neck tension over 0.003 or so isn't "real" neck tension. Once you exceed the elastic modulus of the brass it stretches (or the bullet swages down, if it's got a real thin jacket and soft lead).

So assuming the bullet doesn't deform, a bullet seated with 0.006 neck tension and a bullet seated with 0.003 neck tension will generally have about the same amount of final tension.

If you do load with small neck diameters you should pull one to make sure your bullets aren't losing diameter, if they aren't, you are good to go.

[RiggerJJ]

Keep in mind neck tension over 0.003 or so isn't "real" neck tension. Once you exceed the elastic modulus of the brass it stretches (or the bullet swages down, if it's got a real thin jacket and soft lead).

So assuming the bullet doesn't deform, a bullet seated with 0.006 neck tension and a bullet seated with 0.003 neck tension will generally have about the same amount of final tension.

If you do load with small neck diameters you should pull one to make sure your bullets aren't losing diameter, if they aren't, you are good to go.

Fair enough... I don't deform bullets or ring them with the crimp, and I know there are several ways to get to the final product. The proof is in the pudding so to speak, and with sub-moa accuracy with 223 and 308 I don't think I will be changing much...

I have set up my rifle ammo loading process so that I don't have to handle individual cases other than after they are loaded for gaging, or before starting to sort headstamps. Less time loading means more time shooting!

jj

Edited November 5, 2014 by RiggerJJ

[Raydee38]

just get a lee and be done. they are 12 bucks last time I bought one, might be 15 now.

And if you use your trim die as your only source of sizing you need to expand the neck afterwords with something like a mandrel die. I suggest the 21st Century Shooting expanding dies for no other reason in that they are fairly inexpensive(you buy one body and you can buy multiple expander mandrels for various calibers) and they work great.

The problem I think I will run into with that setup is I don't have enough room on my 550B to run a third die to expand the neck after the cases are trimmed. If I back my sizing die out enough and screw the decapping pin down all the way I am hoping I can decap and expand the neck without much sizing, that way the trimmer can size and trim. I don't want the brass spinning in the trimmer because I already sized it before it got to the trimmer.

[rjacobs]

just get a lee and be done. they are 12 bucks last time I bought one, might be 15 now.

And if you use your trim die as your only source of sizing you need to expand the neck afterwords with something like a mandrel die. I suggest the 21st Century Shooting expanding dies for no other reason in that they are fairly inexpensive(you buy one body and you can buy multiple expander mandrels for various calibers) and they work great.

The problem I think I will run into with that setup is I don't have enough room on my 550B to run a third die to expand the neck after the cases are trimmed. If I back my sizing die out enough and screw the decapping pin down all the way I am hoping I can decap and expand the neck without much sizing, that way the trimmer can size and trim. I don't want the brass spinning in the trimmer because I already sized it before it got to the trimmer.

I didnt realize you were running a 550b. I dont believe there is enough room in to run the mandrel die in station 4. There might be, but I dont think so. I keep meaning to take my die over to my dad's and see if I can get it to fit.