I've used the RCBS collet puller for quiet a few year pulling various LB and HB bullets form brass case 54r ammo to either reduce the charge or replace the bullets with an equivalent commercial SP's to make hunting ammo.

Before you pull the bullet you need to break the seal or crimp on the surplus rd. to make the extraction easier,you can do this by running the surplus rd. up into the bullet seater die.

To do this take the seat plug out or adjust it up high so it doesn't touch the bullet when you run the rd up into the seater die,run the factory rd. up into the die with the ram at full stroke and adjust it down till you feel it touch the factory roll crimp them back the die off a couple turns and lock it down. Next with the rd. at full stroke into the die body adjust the bullet seater plug till it touches the bullet then lower the ram and adjust the seater plug down so it seats the bullet between 1/16 and 1/8 deeper into the case.

Make sure on the RCBS collet puller that you tighten the set screw on the die body lock ring and tighten the die body snug in the press,this will keep the die body for coming loose when you try and release the tension of the pullers collet holding the bullet. Sometime I will get a very light ring where the collet touches the extracted bullet it's not a problem,just make sure you don't over do it when torquing the collet onto the bullet. It just takes a little trial and error to get the feel of it. Once you pull the bullet you will need to resize the case neck so that you have proper tension to reinstall the existing bullet or a new one of same weigh and profile. If you find that the collet puller damages the bullets to much the hammer style pullers will work also there just a little more labor intensive.

On reducing loads in the 8MM I don't shoot one so I cant speak on the powders used in the particular cartridges you have,some powders don't work well when reduced past a certain percentage of case volume and you can get hang fires or SEE Secondary Explosive Effect which can cause bodily harm and destroy you rifle. In my M44 54r using the Bulgarian ammo I've found reducing the factory charge by two grains reduces recoil slightly and is more accurate the ammo is loaded on the warm side anyways. A nice recoil pad such as the Velcro or lace on Kick Killer will work great also.

The best way I have found to enjoy shooting the old military rifles which has substantial recoil is to load your own using cast bullets and powders like Red Dot or Alliant 2400 to name a few. MV are around 1500 to 1600 fps. using these loads and it's like shooting a 22 rf all day long. Hodgdon Powder Co. also offers a powder called TrailBoss that can be used with reduced loads and jacketed bullets that have equivalent MV to the cast loads,a call to Hodgdon can get you the proper data for the 8mm.