300 RUM development?

Slickrick0999 said:

Your advice follows exactly what a friend of mine here locally says. He suggested 88, 89, 90 grain loads for 3 shot groups and possibly have 90.5 or 91 ready if pressure is not seen earlier.
I just worry about "missing a node" by these larger jumps. This is the first time I've had access to a chrono for load development.
I am using H1000 powder as well.
Thanks

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Remember, 1grain = ~1% change in load. As a result, you won't miss a node. Once you find a load that shoots well, then you can experiment with .5grain +/- to fine tune.

Have you found the best COAL? (Cartridge Over All Length) You should do this before working on charge weights.

trebark said:

Remember, 1grain = ~1% change in load. As a result, you won't miss a node. Once you find a load that shoots well, then you can experiment with .5grain +/- to fine tune.

Have you found the best COAL? (Cartridge Over All Length) You should do this before working on charge weights.

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I have not worked on COAL yet.
I'm shooting 215 hybrids and keeping them about 5 thou off lands.
I have only fired 6 rounds on this gun cleaning after each just to do a little break in.

My recommendation would be to work on COAL first. Experiment with different lengths until you find what works best. Use your 88grain load for all experimentation. Then once you have determined best COAL, then start increasing the charge weight.

Key to reloading is to only change one variable at a time. This way you can measure the effect of the change.

I went with Bartlein barrel.28 in,1/13 twist Shooting 168 Berger's Norma MPR Powder. Shoots really great .Nothing has ever gotten away. For me it's a great sit up

For a hunting rifle, H1000 is a great choice due to its temp stability and consistency. I use it for 210/215 loads in several .300RUMs.

trebark said:

My recommendation would be to work on COAL first. Experiment with different lengths until you find what works best. Use your 88grain load for all experimentation. Then once you have determined best COAL, then start increasing the charge weight.

Key to reloading is to only change one variable at a time. This way you can measure the effect of the change.

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Trebark,
Would you mind sharing your method on COAL testing? Increments of change & number of rounds? Do you use chrono data with or for anything?
Thanks for your help

tbrice23 said:

I'll probably do .7gr increments of Retumbo, 3 shot groups. When I think I've struck gold I'll load 5 or 6 round group to verify.

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Yes to what you've stated BUT YOU'RE NOT FINISHED. Start playing with your Seating Depth to ENHANCE the BEST LOAD you've gotten from WHAT you've done already! It gets better, A LOT BETTER! Theosmithjr

Test COAL the same way you test charge weights. Hold the charge weight constant at 88grains of H1000. Then load three or five rounds each of .002", .010" and .015" off the lands. (you have already tested .005"). Go ahead and run every round over the chrono (shooting without a chrono is like shooting with your eyes closed). Then examine each group and see if there's any kind of a sweet spot. Given that you are shooting the berger hybrids, they are not particularly depth sensitive. So you should not have a big problem finding the optimal COAL. Once you have the optimal COAL, then start working on charge weights.

theosmithjr said:

Yes to what you've stated BUT YOU'RE NOT FINISHED. Start playing with your Seating Depth to ENHANCE the BEST LOAD you've gotten from WHAT you've done already! It gets better, A LOT BETTER! Theosmithjr

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Yes.
I shoot a lot of Hybrids and even though they're not supposed to be jump sensitive my 28 nosler likes the 175 Elite hunters at .093" jump best by far. Interestingly enough my 300 WM likes 185 Hybrid targets at .095" jump also.

tbrice23 said:

Yes.
I shoot a lot of Hybrids and even though they're not supposed to be jump sensitive my 28 nosler likes the 175 Elite hunters at .093" jump best by far. Interestingly enough my 300 WM likes 185 Hybrid targets at .095" jump also.

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That's why when in SEARCH OF ULTIMATE ACCURACY from your Handloads, you load for your best, safest load in ALL TEMPERATURES, then to even make it MORE ACCURATE you start Experimenting with Seating Depth! I strive for PERFECTION, BUT ALWAYS SAFETY FIRST! I DO NOT EVER consider a PETLOAD SAFE until I fire it in the HEAT of a SUMMER AFTERNOON! If she still groups in SUB MOA's, shows NO SIGNS of PRESSURE, THEN & ONLY THEN DO I MASS LOAD IT! I'm talking about putting an ammo box of 100 or 200 together for hunting & range shooting. But I also DOCUMENT EVERY STEP from the moment I purchase, build, and load for any weapon! Saves Time & Money, both on the Bench & at the Range!
Theosmithjr

I REALLY would love to load 200 rounds up but in most of the cartridges that I load for I'm afraid the that the throat will change enough to loose enough velocity to knock my out of that particular accuracy node... then I'm dumping rounds. Talk about wasting time.

I only have 100 pieces of new brass to work with right now. I would love to get a load and have them all ready to go but I don't see that happening.
I'm a steel shooter and these will be used for 1000 to ??? On steel so the goal will be as much velocity without deterioration of accuracy.

tbrice23 said:

Did you have any pressure sighs with 88 gr of H1000?

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88 is a fairly middle of the road load for the RUM. I didn't start seeing pressure signs in mine until around 91 gr with H1000 (accuracy went to hell over 90 though). That is with the 212 ELDX which is similar to the Berger 215.
OP - H1000 is a good powder for the RUM but if you're looking to try another one, get a pound of Retumbo. Work up just as you did with H1000 but mine like about half a grain more Retumbo vs H1000 with all else being equal. It's a little slower (for me at least) but accuracy is better across a broader range with the Retumbo...for me in my rifle anyway.

I too found Retumbo to be a little more consistent than H1000 in ES in my RUM. I settled at 88 gr, with Federal 215m and Nosler brass. My 7mag prefers H1000, so it's rifle dependent I suppose. I started to see some light cratering at 91gr, and backed off a few grains for an acceptable working load. For me. With the 215 Bergers, I did not find much change in accuracy when playing with seating depth. When I first started with the 210 VLD hunting bullets, they liked a .004 jump the best. But the 215 hybrids seem to have a fairly wide range I can jump them. Way more than one would think. If you feel you're getting close to max by working up from 88gr in ½ grain increments, then back it on down a couple grains for safety, and tinker in slight increments from there in seating depth and charge weight... if you're a "tinkerer". Here is link to an old thread about Bergers and seating depth if you have not seen it: https://www.longrangehunting.com/th...-from-berger-vld-bullets-in-your-rifle.40204/