I am new to the 300 HAM'R.....just used a Wilson Combat barrel to convert a Aero Precision 5.56 that I just did not shoot. I have been shooting and loading 300 AAC with no real issues. I have a question regarding some of the loads I am seeing being floated around. I am in the process of setting up my Dillon 550C and the first thing I notice is the case capacity. I am planning on using CFE BLK, have had good luck with it on some loads with AAC, particularly heavy subsonic.

When I look at the range of bullets recommended to the HAM'R, the lighter rounds like the 110 Hornady Max are running up to 29 gr of CFE BLK. I am using Starline brass and at about 26 grains, the case is filled up to the bottom of the neck. I don't have any experience with compressed rounds but it sure seems like that is going to be very compressed with 29 grains.

With heavier bullets, in the 125 range the loads get down around 26 gr.

My questions are this: With lighter bullets, would I be better off using another powder. Can you really get 29 gr into that case and not compress it too much. I have no idea how much is too much.

The 300 HAM'R has not really caught on in Montana (where I live) and none of my shooting/reloading friends have any experience with that round. I am the group guinea pig on HAM'R

Thanks for any advice on this..........

Maybe this helps?
https://www.handloadermagazine.com/shooting-the-300-ham-r
Watch the loaded length. For the 110 Vmax (300 BO) I keep about 1/2 drive band in the neck, bout longest mag will take.

I have read that 110gr is about as heavy a bullet where AA 1680 is appropriate for top velocities. I have never used AA 1680 in the 300 Ham'r. If you go over to the 300 Ham'r thread on this forum you will find it encyclopedic in content. The good thing about CFE BLK is it's nearly impossible to make an over pressure load (this is not a challenge guys!). Yes, sometimes it's tough to get all the powder in and leave room for the bullet. The severity of that depends somewhat on the bullet and what brand of case you are using. I use mostly Starline cases. Their high quality is good but they have the least internal volume you'll typically find. You don't want to seat any bullet out so far it is in the lands. So you have some homework to do and the exact answer varies by bullet design.

If you are looking for high end loads you will probably have pretty full cases. That's tough trying to make the 550 seat the bullet when the powder won't let it. I throw my charges and put all the cases in a tray. Then take some sort of vibrator (My Dremel tool set on medium does the job) to gently vibrate the tray from underneath to get the powder deeper in the case. It does not make a big difference with ball powder but it makes enough difference to allow the bullet to seat without a lot of back pressure.

There is lots of loading data over on the Wilson Combat website. Good luck. Great cartridge.

Thank you for both of those responses. I do appreciate it. After looking at all of this, I think will stick with the heavier bullets.... 125 Controlled Chaos and Hornady 125 FMJ until I get a little more experience with the HAM'R. I can't wait to try it .

I may give that a try. I can easily prime and charge with the Dillon, put the charged cases in an ammo tray and settle the powder...back to the Dillon to seat and crimp. Curious to see how much it settles with the CFE BLK.