Bullet RPM and accuracy

[justin davis]

Let’s talk Bullet RPM…Berger recommends 300,000 max and Hornady recommends 290,000. Does accuracy degrade if your over the recommended max? Is there any downside other than if you’re spinning too fast and bullets are blowing up?



I’ve been messing with some Hornady ELDMs in a 22 creedmoor. They are going 3450. They are 310,000 rpm if I calculate it right. They don’t seem to shoot that well. There will be a tight group but then I get one or 2 random flyers. I’m wondering if I am spinning the bullets too quick. Or maybe the barrel just doesn’t like the bullets and it’s unrelated to the rpms. Wonder if I slow it down if they would shoot better?

 

[RockAndSage]

Man, that's a great question. A good control would be if monos started sending fliers above 300krpm.

Does a traditional bullet have to blow-up entirely, or could the fliers be from just a little separation between jacket and core?

 

[180ls1]

Man, that's a great question. A good control would be if monos started sending fliers above 300krpm.

Does a traditional bullet have to blow-up entirely, or could the fliers be from just a little separation between jacket and core?

My mono gun is @ 350K and is by far the most accurate one I own. 7" 6.5 @ 3400 with 124hammers. It also has shock dropped more animals in their tracks than anything else I own.

 

[waspocrew]

My 22 CM is spitting 62 ELDVTs at like 350,400. Absolute lasers. 1:7.5 twist at 3650 FPS. None have blown up in flight.

 

[willfrye027]

It’s a very interesting question I was also thinking about this after listening to Aaron Davidson on the rokcast.

In my 24” 22 creedmoor i worked up a load with both 80eldm going somewhere near 3400 (318k RPM) and 88 eldm going around 3180 (297k RPM).

The 80s were shooting SO good! Like 8 or 9 shots into .5”. But then in larger groups there would be a “flier” or two and the 15 shot groups were opening up to 1.5” or a little more. That repeated over a couple groups.

The 88s were consistently shooting right at 1.1” without any “fliers” for 15 shot groups. Just a nice normal looking round group.

I’m well aware this could be noise from small sample sizes but I do shoot larger groups and the 80s really seem to have some wild fliers in there…I wonder if that was RPM related..


Edit to add in a previous barrel I was blowing up 88s in the 320k RPM range fairly consistently, that is a separate thing in my mind

 

[TxLite]

My 22 CM is spitting 62 ELDVTs at like 350,400. Absolute lasers. 1:7.5 twist at 3650 FPS. None have blown up in flight.

I’d be interested to see if they start after you get some erosion

 

[waspocrew]

I’d be interested to see if they start after you get some erosion

Could happen - I’ll have to check my notes, but I’m probably sitting at least 500 + rounds down the barrel.

 

[wapitibob]

Let’s talk Bullet RPM…Berger recommends 300,000 max and Hornady recommends 290,000. Does accuracy degrade if your over the recommended max? Is there any downside other than if you’re spinning too fast and bullets are blowing up?



I’ve been messing with some Hornady ELDMs in a 22 creedmoor. They are going 3450. They are 310,000 rpm if I calculate it right. They don’t seem to shoot that well. There will be a tight group but then I get one or 2 random flyers. I’m wondering if I am spinning the bullets too quick. Or maybe the barrel just doesn’t like the bullets and it’s unrelated to the rpms. Wonder if I slow it down if they would shoot better?

I had the same flyer issue spinning 143's at 312,000 but couldn't tell if it was spin rate or just the rifle not liking solids.