Velocity-Looking for Insight

[AF Shooter]

I am the proud owner of a new SSG custom (Thanks Nate) and the rifle is truely awsome. The rifle shoots well under 1/2 moa and Nates new brake makes this a real pleasure to shoot.

.300 RUM
Phoenix action w/ PTG bolt and Sako extractor
Broughton 5C 28" heavy Palma
Mcmillan A5 Adjustable
Seekins detachable mag system
Jewel trigger
Night Force 5.5x22x50 NPR2 zero stop

My problem is that the velocity seems low for this set up and I was wanting to be around 3200 fps with Berger 210 BT Target bullets. I am getting pressure issues at anything over 3000 fps.

Berger 210 BT Target
Remington brass
Retumbo powder
GM215M primers
.010 off land
results do not change if necks turned or not or if using .335 or .336 bushings
165 rounds thru rifle now

Chrono results:

90 grns- 2990 fps
91 grns- 3088 fps
92 grns- 3060 fps
94 grns- 3170 fps

90 grns is only one that does not have pressure issues. With others the I get bolt lift on last 1/4" of bolt cycle and loose primer pockets at 92 grns. Velocity jump between loads seems high and the 92 lower than 91 is odd.

Really want more speed and appreciate any insight with this.

Terry

 

[Mikecr]

Are you sure 3200fps is possible with a 210gr bullet from a RUM, without running dangerously excess pressures?

I don't have one, but reviewing your cartridge in QuickLoad, and running what-ifs, I have to conclude that you'll never get there.
QuickLoad shows me that 90gr Retumbo & your bullet equates to SAAMI Max. It's gets ugly from there.

Maybe I'm missing something though...

 

[yorker]

+1 on mikecr comment

sounds like you are asking a lot for 210's

 

[AF Shooter]

Thanks for the reply and Quick load data. I have a stock Sendero that I get 3188 fps with 96grns Retumbo and no pressure issue.

Many posts on here show others getting between 3100 and 3200 regularly. Even Berger data lists 92 grns as a load for the 210.

Like many I have an need for speed but am very lucky to have such an accurate rifle

 

[trueblue]

I would not worry about an extra 100 fps if you are getting 1/2 MOA accuracy. My question is how far out is it a 1/2 MOA rifle. If it is accurate for the distances you are going to hunt, then stick with that accuracy load, work up your drop chart and enjoy. After toying with that same dilema for awhile I came to the conclusion that accuracy and low extreme spreads are much more important to me, than 50-100 fps.

 

[Mikecr]

This is a good place to filter through what others are getting:
10 loads available in .300 Remington Ultra Magnum with powder equal Hodgdon Retumbo

 

[AF Shooter]

I have shot for 5 shot groups to 300 and busted rocks to 850. Everthing is great and all the loads are accurate.

Pretty good advice trueblue. I am at the same point and seeing if I am missing anything that someone else has encountered.

Thanks for the link Mikecr definately more interesting data.

 

[remingtonman_25_06]

Me thinks your asking a bit much from the 300 RUM as well with 210g bullets.

I had a 300 RUM and put a lot of 210's through it as well at 3000fps, but granted I had a factory 26" tube. Accuracy was great, and it was about max right there. I was using H1000 at 88g and Retumbo at 89-90g.

I could go to 3100fps pretty easy, but groups opened up considerably more, and so did pressure.

Woulnd't think of trying to get to 3200 and still have stellar accuracy w/out getting high in pressure.

 

[AF Shooter]

I decided to go with a load that was both accurate and low pressure of 90.2 grns and head to the range yesterday. 5 shots over chrono with avg of 3112 and an ES of 14 over my Oehler 35P. Very happy with the results and no pressure issues.

Groups were .252" at 100 yards and 2 groups of .750" at 200 with a heavy mirage in the AZ desert.

Only differnce was an thorough cleaning paying particular attention to throat.
I had heard that these barrels would break in and show an increase in velocity. Only thing I can think of for the change.

 

[mciver]

Are you stuck on the Rutumbo? I had a hell of a time using Rutumbo in my 30's and changed to RL25...used less powder and had better results in accuracy, velocity and pressure. Good powder for 300's....just a thought.

 

[AF Shooter]

Not really, but I have a bunch stocked up. What bullet are you shooting and what kind of results did you get? Loads and velocity Retumbo vs. RL-25.

Thanks

 

[J E Custom]

I am the proud owner of a new SSG custom (Thanks Nate) and the rifle is truely awsome. The rifle shoots well under 1/2 moa and Nates new brake makes this a real pleasure to shoot.

.300 RUM
Phoenix action w/ PTG bolt and Sako extractor
Broughton 5C 28" heavy Palma
Mcmillan A5 Adjustable
Seekins detachable mag system
Jewel trigger
Night Force 5.5x22x50 NPR2 zero stop

My problem is that the velocity seems low for this set up and I was wanting to be around 3200 fps with Berger 210 BT Target bullets. I am getting pressure issues at anything over 3000 fps.

Berger 210 BT Target
Remington brass
Retumbo powder
GM215M primers
.010 off land
results do not change if necks turned or not or if using .335 or .336 bushings
165 rounds thru rifle now

Chrono results:

90 grns- 2990 fps
91 grns- 3088 fps
92 grns- 3060 fps
94 grns- 3170 fps

90 grns is only one that does not have pressure issues. With others the I get bolt lift on last 1/4" of bolt cycle and loose primer pockets at 92 grns. Velocity jump between loads seems high and the 92 lower than 91 is odd.

Really want more speed and appreciate any insight with this.

Terry

Don't let other peoples velocity bother you. your velocity will be what ever the rifle decides
it will be.

All rifles are different and different barrels make a difference in velocity with the same load.

I would recomend that you work up to the point that you see pressure signs and then back
off one or two grains on the powder charge. then play with different seating depths to get the
best accuracy. (the further away from the lands the lower the pressure normally).

Your factory rifle may have more free bore than your custom so don't try to compare the two.

Accuracy is more important than velocity . So work in that direction and let the velocity fall
where it will.

Just my 2 cents

J E CUSTOM

 

[mciver]

J E has a great point...accuracy should always be the goal...not speed. Having said that, as I stated earlier, I had bad results with rutumbo. I originally loaded it in my custom 30-378(very similar in velocity to your RUM). I used 113gr...as it stated on the can and all I can say is...Holy ****!. first three 180gr scirrocos were coming out at nearly 3800 fps and I could barely get the bolt open. I got the pics of the chrony cuz everyone standing around almost **** themselves. I immediatly pulled the remaining bullets and re-weighed the powder and it was right on at 113gr. Grabbed new brass and primers..same thing. Went to RL25...108gr with 200gr accubonds and averaged 3325 with them...no excessive pressure, no primer issues and brass was spot on after the shot. Just my experience. RL25, 22, H1000 and 7828 are my main choices now. $25 bucks for a can a powder isn't too bad to see if it works better than what you already have.
www.reloadersnest.com is a good source to play with.

 

[Varmint Hunter]

I had what appeared to be some pressure issues with most powders in my 300RUM with heavy bullets unless I ran them at 300 Wby velocity. Well ...... if I wanted 300 Wby velocities I would have bought a 300 Wby. Soooo I keeep experimenting with different powders until I tried Hogdon's US869. 101.1gr of 869 will push the 210VLD out of my 27" Broughton @ 3,150 ft/sec. I could probably get even more velocity but I'm getting sub 1/2moa groups at that speed so I'll leave well enough alone.

You might just want to give the US869 a try.