300 PRC Hammer 199 Retumbo/N565

[Shane Lindsey]

In my experience FWIW, I always needed more jump with the Hammers. I think you should retest at .050" off lands. I tried to load them long and sexy in my 308, 300 WM, 6.5x284, 300 RUM and they seemed to like a little more run at them. Might be worth a try.

 

[RockyMtnMT]

I think you might be too close to the lands. When I can reach the lands I start at 20 thou off. Closer than that and it seems you can see some pressure spikes. The drive band design is for reducing the amount of contact in the bore but it also reduces contact in the case neck. Sometimes the primer ignition will jump the bullet before the powder gets going pushing the bullet in the lands when the powder ignites can cause erratic pressure. A little more jump and possibly a little more neck tension.

You are correct. They generally are not sensitive to seating depth but I think you will be better off 20 thou off so off. They certainly don't mind jumping.

 

[ButterBean]

I think you might be too close to the lands. When I can reach the lands I start at 20 thou off. Closer than that and it seems you can see some pressure spikes. The drive band design is for reducing the amount of contact in the bore but it also reduces contact in the case neck. Sometimes the primer ignition will jump the bullet before the powder gets going pushing the bullet in the lands when the powder ignites can cause erratic pressure. A little more jump and possibly a little more neck tension.

You are correct. They generally are not sensitive to seating depth but I think you will be better off 20 thou off so off. They certainly don't mind jumping.

I agree with Steve on being to close to the lands, I seat to the last PDR groove if the powder charge will allow it and I would pull your expander ball if you haven't already

 

[Recon$$]

Thanks guys, I'll run it back .050 and last PDR groove and see if that gives me a node.

 

[ButterBean]

Thanks guys, I'll run it back .050 and last PDR groove and see if that gives me a node.

Let us know what happens and just holler if you need anything 812-264-6183

 

[jessej]

Thanks guys, I'll run it back .050 and last PDR groove and see if that gives me a node.

Use caution. I did this.
I am running 151 absolutes in a RUM at full mag length, I decided to seat down to the last PDR for a test. my groups opened way up and the load went from being warm to waaaay to hot, (rubber hammer to open bolt). I fully expected to see a reduced sign of pressure but got the opposite. I've been gonna pick Beans brain in this subject but haven't gotten to it yet.

 

[ButterBean]

Use caution. I did this.
I am running 151 absolutes in a RUM at full mag length, I decided to seat down to the last PDR for a test. my groups opened way up and the load went from being warm to waaaay to hot, (rubber hammer to open bolt). I fully expected to see a reduced sign of pressure but got the opposite. I've been gonna pick Beans brain in this subject but haven't gotten to it yet.

Just give me a holler

 

[ButterBean]

Use caution. I did this.
I am running 151 absolutes in a RUM at full mag length, I decided to seat down to the last PDR for a test. my groups opened way up and the load went from being warm to waaaay to hot, (rubber hammer to open bolt). I fully expected to see a reduced sign of pressure but got the opposite. I've been gonna pick Beans brain in this subject but haven't gotten to it yet.

Did you start low on the charge once you seated deep?

 

[WYOHTF]

I agree with Steve on being to close to the lands, I seat to the last PDR groove if the powder charge will allow it and I would pull your expander ball if you haven't already

@ButterBean
Last on top - or bottom ?
The statement about "if the powder charge will allow it" led to thinking you may be seating to the last on top if you aren't crunching powder.

 

[jessej]

No sir. Seated a few that were already loaded.

 

[ButterBean]

No sir. Seated a few that were already loaded.

The last PDR groove on top and you will need to start your powder charge at the bottom ad work up again, What is your neck interference?

 

[jessej]

I'm ashamed to say I don't know what my neck tension is. I'm still climbing the mountain of acceptable concentricity. Neck tension is on my list of things to accomplish

 

[ButterBean]

I'm ashamed to say I don't know what my neck tension is. I'm still climbing the mountain of acceptable concentricity. Neck tension is on my list of things to accomplish

What kind of die are you using ?

 

[jessej]

Got several sets. Rcbs, horn, redding. Redding is what I have the best luck with