300 RUM with 210 BERGERS

[Gary Morgan]

I'd like to post some info here for whatever help it may be to others and also would like to hear any comments about the meaning of the data and which load you would use for long range hunting.


RETUMBO W/210 BERGERS IN 300 RUM, ALL GROUPS WERE 3 SHOTS. 28-INCH KRIEGER BARREL. BARREL WAS NOT CLEANED DURING TESTING.

91 GRS. – 3,034 FPS – ES 37 – SD 15.10, GROUP SIZE - .705

92 GRS. – 3,019 FPS – ES 32 – SD 14.85, GROUP SIZE - .484

93 GRS. – 3,099 FPS – ES 32 – SD 14.24, GROUP SIZE - .496

94 GRS. – 3,099 FPS – ES 42 – SD 17.46, GROUP SIZE - .175

95 GRS. – 3,133 FPS – ES 43 - SD 17.75, GROUP SIZE - .715

96 GRS. – 3,168 FPS – ES 62 – SD 26.15, GROUP SIZE – 1.291

 

[trueblue]

Thanks for the work in putting the data together.
However, I would still try for lower ES.

 

[J E Custom]

I'd like to post some info here for whatever help it may be to others and also would like to hear any comments about the meaning of the data and which load you would use for long range hunting.


RETUMBO W/210 BERGERS IN 300 RUM, ALL GROUPS WERE 3 SHOTS. 28-INCH KRIEGER BARREL. BARREL WAS NOT CLEANED DURING TESTING.

91 GRS. – 3,034 FPS – ES 37 – SD 15.10, GROUP SIZE - .705

92 GRS. – 3,019 FPS – ES 32 – SD 14.85, GROUP SIZE - .484

93 GRS. – 3,099 FPS – ES 32 – SD 14.24, GROUP SIZE - .496

94 GRS. – 3,099 FPS – ES 42 – SD 17.46, GROUP SIZE - .175

95 GRS. – 3,133 FPS – ES 43 - SD 17.75, GROUP SIZE - .715

96 GRS. – 3,168 FPS – ES 62 – SD 26.15, GROUP SIZE – 1.291

For long range shooting/hunting you are looking for the lowest SDs, Best group and most consistant load combination.

It looks like your rifle likes the 94 grain load + or - . and the fact that the velocity did not
increase from 93 to 94 grains would indicate a change in primers may be nessary.

Also I would recomend that you clean between each group for more consistant data. (clean,
shoot one fouling shot and then shoot the 3 shot test load). repeat this each time because
as the barrel fouls the data will become less viable.

Lower standard deviations will give you less elevation error at longer distances . so try to
lower them to somewhere arround 10 or 12 or lower.

Once you get the best consistency of velocity.SDs and groups then experiment with bullet
seating depths for the ultimate load.

Just a recommendation.

J E CUSTOM

 

[jmden]

Just an fyi, my 300RUM load with 210's and Retumbo (factory 26" barrel) is 94.7g at just under 3K acc'd to exbal using Litz's bc numbers, but about 3020fps with my chrono. It is very consistent.

Edit: Got called away and couldn't finish this post...

-.010 and ~3.845 OAL and FED 215M. Interesting that your 94g load grouped best and that's close to where I am. Might be a sweet spot with the RUM and 210's.

That ES is quite odd. What are your reloading techniques--close to or essentially benchrest techniques I'm guessing?

 

[Gary Morgan]

J E Custom, thanks for your response. I am curious what primer you would suggest I change to. I am using the Federal Gold Medal Match Magnum primer. I thought it was odd that the 91 grain charge was faster than the 92 grain load, and then 93 and 94 shot the same speed.

I have the bullets about .010 into the lands, and I was anticipating maybe getting 3,200 FPS out of the 28-inch barrel. I wonder if I should try moving the bullet back off the lands to hopefully gain a little velocity.

What do you think?

 

[J E Custom]

J E Custom, thanks for your response. I am curious what primer you would suggest I change to. I am using the Federal Gold Medal Match Magnum primer. I thought it was odd that the 91 grain charge was faster than the 92 grain load, and then 93 and 94 shot the same speed.

I have the bullets about .010 into the lands, and I was anticipating maybe getting 3,200 FPS out of the 28-inch barrel. I wonder if I should try moving the bullet back off the lands to hopefully gain a little velocity.

What do you think?

I think you are on the right track with 94 grains of Retumbo. there seems to be a lot of RUMs
that like this load. go up or down in 2/10ths grain increments and you will find the NODE.

I all start with the bullet farther away from the lands so that I can find the MAX load without
any problems and then adjust the seating depth to tweak the load.

I would back off to .020 to .025 to start with and try that first. I like the 215 M but would
try a 91/2 rem primer or a 215 (NO Match) they are a little hotter so watch for pressure
signs.

The other thing that could be effecting SDs is bullet grip . check neck thickness and if it varies
you need to turn them for a more consistant grip on the bullet.

For best results only make one change at a time or you may mask a really good load potential.

The RUMs are very forgiving and load development should go fast if you are careful to keep
tract of any changes.

The only problem I have with the Retumbo is that it can become critical (Over pressure) very
easy and case density is not where I like it.(I prefer 99 to 100%) but it does have it's following.

Just some thoughts.

J E CUSTOM

 

[25 Otter]

+1 with the neck tension observation. I was a doubting Thomas until I started working with a PPC for 100 and 200 yd BR. I can tell you I don't miss case prep chores since leaving the game.

I have to agree with J E Custom again with his choice of primer. If it's Retumbo, for me it's the 215 non M. My experiance has been with 200gr Noslers,as opposed to the Bergers though.

 

[Gary Morgan]

Thanks for the input, guys. I'll surely consider your suggestions, but first I'm going to try to see how repeatable that .175 group is with 94 grains. If it continues to shoot 4/10ths or less, I think I'm in Nirvana. No need to wear out a barrel looking for the Holy Graile. Once again, thanks for the input. I don't think it makes a lot of difference, but I forgot my target backer yesterday and set the target up on the berm, so these groups were shot at 110 yards instead of 100.

 

[Gary Morgan]

Just an fyi, my 300RUM load with 210's and Retumbo (factory 26" barrel) is 94.7g at just under 3K acc'd to exbal using Litz's bc numbers, but about 3020fps with my chrono. It is very consistent.

Edit: Got called away and couldn't finish this post...

-.010 and ~3.845 OAL and FED 215M. Interesting that your 94g load grouped best and that's close to where I am. Might be a sweet spot with the RUM and 210's.

That ES is quite odd. What are your reloading techniques--close to or essentially benchrest techniques I'm guessing?


JMDEN,
I'VE BEEN SHOOTING NBRSA SHORT RANGE BENCHREST MATCHES FOR 10 YEARS OR SO, SO I IMAGINE A LOT OF THAT BLEEDS OVER INTO ALL MY RELOADING. BUT WITH THE RUM, I BOUGHT REMINGTON BRASS, WEIGHED AND SORTED THE 100 CASES I BOUGHT INTO ROUGHLY TWO GROUPS AND CHAMFERED THE CASE MOUTHS, SLID A BULLET IN PLACE, MEASURED THE LOADED CASE NECK WITH A VERNIER CALIPER. I WAS REALLY SURPRISED TO FIND THAT THE CASE NECK THICKNESS VARIED LESS THAN A THOUSANDTH ALL THE WAY AROUND THE NECK ON THE CASES I CHECKED. I SPENT MORE TIME FUSSING WITH WHERE TO START WITH THE BULLET SEATING DEPTH THAN ANYTHING. I FINALLY SET THE BERGERS AT ABOUT .010 INTO THE LANDS AND LOADED THE CASES USING AN RCBS CHARGEMASTER.

I LET THE BARREL COOL WITH A WET TOWEL ON IT BETWEEN EACH GROUP FOR 5 TO 10 MINUTES BEFORE SHOOTING THE NEXT ONE.

I WAS SURPRISED AS ANYONE WHEN THE 92, 93 AND 94 GRAIN GROUPS COULD ALL BE PUT ON TOP OF EACH OTHER AND MEASURED LESS THAN 1/2 INCH. THE GROUPS ALL FORMED AT THE SAME STOP ON THE TARGET AND RESEMBLED EACH OTHER VERY MUCH IN SHAPE EXCEPT THE .175 GROUP LOOKED LIKE A 3-LEAF CLOVER WHERE THE OTHER TWO GROUPS HAD TWO BULLETS TOUCHING AND THEN ONE JUST A LITTLE OUT OF THE GROUP.

I'M GOING TO TRY THE 94-GRAIN LOAD AT 500 YARDS SOMETIME SOON AND SEE IF THE VERTICAL IS GOOD OR NOT.

 

[Gary Morgan]

Hey, guys, I'm done. I went to the 500-yard range today and shot my 300 RUM with the 94 grain Retumbo load, 210 Berger and Winchester Large Rifle Magnum Primers. It was about 20 degrees hotter here today at about 11:30 a.m. CDST, about 85 to 87 degrees.

I set up my 35P Oehler, got my gun sighted in on some clays at 500 yards and shot one three shot group over the chrono. It averaged 3,175 FPS with a 5 FPS ES and 2 FPS SD. THe wind was in my face, about 10 MPH straight on. The group measured 1.963 inches. The biggest change to my load was the Winchester primer, and I took off a 3.5x15x56 NXS and put on an 8x32x56 NXS, which made holding on the target much more consistent.

I appreciate everyone's input. It all helped me get to my goal of 2 inches or less at 500 yards. I now feel like I can take 600 to 800 yard shots on deer with confidence and feel like I've put in enough work to legitimately take such a shot.

Gary Morgan