i have another question, I tried pulling some bullets with an rcbs bullet puller with the .40 collet, no dice very hard to get them out, VERY!! I read when you expand the case mouth to expand just enough so the bullet will sit, the bullets seat easily enough, the case does not show signs of buckling, now the question, should I flare the case mouth more ?? I made up some dummy bullets by backing off the crimp all the way, seated the bullet to 1.260, then backed the seater out and hand turned the crimp down without using the lever on the reloader, removed my barrel from the gun and they dropped in nice with no resistance, put the gun together and they cycled great. Should I flare the case mouth more ?? I ordered 1000 RMR 180 gr bullets, waiting on them, picking up the Blu Dot this weekend. Thanks in advance for any answers

I only use a kinetic bullet puller, so no experience with the RCBS.

As long as you are belling the case mouths enough that the bullets sit in place and are seating straight without damaging the bullet or brass, you're fine. Too much flare (belling) just shortens the life of your brass overworking it.

10mm brass has pretty thick sidewalls compared to lower pressure calibers, like .45acp. It always takes a lot more whacks with my kinetic puller for 10s. That case neck tension isn't a bad thing. If these are the plated bullets that you may have over crimped, you may have cut into the plating with your crimp and that will make them harder to pull.

Did you actually get one out? Can you see any damage?

I'd have to agree with Greybeard about over crimping. I have the kinetic puller and the RCBS collet type. The collet type set up correctly will remove the bullet easiest. If you can't get the bullet out with a collet type puller, something is wrong and over crimping is probably it. I would not expect any accuracy from any bullet, plated or not, that is crimped too much. Unless you're on a tight shooting budget, I'd just shoot what you have for trigger training time and don't expect any accuracy. You'll end up with good brass assuming you find it. If you just need to pull the bullets, the collet can be tightened down so hard on a bullet that it will pull it but it will destroy the bullet. I'm assuming something like a Rockchucker press.

I use the below puller and still requires a a few hard wacks. I do however use a 6 x 4 x 4 chunk of wood for this, an idea I received from Shadow or one of the other guys

Ken

RCBS Pow'r Pull Kit https://www.amazon.com/dp/B004Y6YP4I/ref=cm_sw_r_cp_api_i_Aj8fEbGGTEHFC

OK about the case flair, you want the opening just enough for the bullet base to just fit inside with Jacketed...slightly more if using a cast bullet to prevent shaving bullet material off while seating.
It is wise to seat the bullets fully with no crimp being applied.  Dies with a taper crimp need to be raised at least an 1/8" or slightly more to avoid the die closing the case back against the bullet as it is being seated.  I use a 1/8" spacer ring under my RCBS seater/crimp locking ring to raise mine up.
Then I remove that spacer ring adjust the seater stem back out to apply the taper crimp to finish my rounds...You can place the seater stem down to where it touches the bullet's nose at the top of the stroke because the bullet is not going to move much or at all at this point!  I like to see a slight shine on the very edge of the case mouth where it contacts the taper and it is being pushed back against the bullet... If you measure the very edge of the case mouth when finished you should see 0.4215" to 0.4225" depending on the brass and bullet actual sizes.

Now the Kinetic puller, I have an older RCBS with the aluminum shaft, I only smack it on a piece of 4" x 4" block that is 24" long as it stands up on the floor.  When you strike the Kinetic puller against the block you will not want it to bounce. Think of a "Deadblow" hammer here.  Observe you bullets movement and adjust the strike force to just have the bullet drop free and not splash the powder around.  Also if you are pulling soft point bullets or other bullets that you DO NOT want to damage the noses, place a foam ear plug inside the puller to cushion the bullet as it drops out!

Insuring the inside of the puller is clean makes powder recovery much easier.  As you remove the contents do so over a clean sheet of typing paper just incase some powder spills, I usually pour into my scale pan sitting in the middle of the typing paper...the finer powders love to get away... LOL 

If you all have visited the pull down documentations you'll see I have pulled tons of bullets over the years here.  Since 1978 I have actually worn out the original 3 jaw chuck doing bullet removals.

That's it for now have fun!

Thanks Shadow, I was pretty confident I got the 4x4 wood smack from you!

Ken