Retumbo or H50BMG in 32" 300 RUM?

[MontanaRifleman]

For the sake of objective discussion, I propose that there is no such thing as a "stable" powder and I don't think I'll get any debate on that... unless maybe you think a 7RM can out pound a 300 WM . I think we can safely assume that some powders are more stable than others. If there was a powder or powders that were completely stable, I would certainly give them the highest priority in selection.

So, understanding that any and all powders will have deviations in performance with temp changes, we should know that there should also be adjustments in our ballistic solutions based on those deviations. The adjustments might be smaller or greater but they still need to made for long range precision and accuracy.

Some other considerations in the big picture are

Load Density - the closer to 100% capacity, the better for more consistent performance

Load ES - the reason should be obvious

Load/Rifle Precision, meaning which powder does the rifle like best? - see the above

The assumption, although not proven, is that Retumbo is "more stable" than RL33. I would agree that it's probably a good assumption. Based on the above, my question is.... so what?

Being a slower powder, RL33 will increase load density. It will also increase velocity. I find those two benefits appealing.

Whether or not it gives a good ES and/or likes the rifle will vary from rifle to rifle and other variables like brass, primers, reloading techniques, etc.

If it gives me good load density and velocity, I'm not going to write it off because it might be a little more unstable than Retumbo. I'll do my part to make it work and make the adjustments when needed.

http://www.longrangehunting.com/forums/f17/338-allen-xpress-rl33-load-development-120353/

 

[Tumbleweed]

For the sake of objective discussion, I propose that there is no such thing as a "stable" powder and I don't think I'll get any debate on that... unless maybe you think a 7RM can out pound a 300 WM . I think we can safely assume that some powders are more stable than others. If there was a powder or powders that were completely stable, I would certainly give them the highest priority in selection.

So, understanding that any and all powders will have deviations in performance with temp changes, we should know that there should also be adjustments in our ballistic solutions based on those deviations. The adjustments might be smaller or greater but they still need to made for long range precision and accuracy.

Some other considerations in the big picture are

Load Density - the closer to 100% capacity, the better for more consistent performance

Load ES - the reason should be obvious

Load/Rifle Precision, meaning which powder does the rifle like best? - see the above

The assumption, although not proven, is that Retumbo is "more stable" than RL33. I would agree that it's probably a good assumption. Based on the above, my question is.... so what?

Being a slower powder, RL33 will increase load density. It will also increase velocity. I find those two benefits appealing.

Whether or not it gives a good ES and/or likes the rifle will vary from rifle to rifle and other variables like brass, primers, reloading techniques, etc.

If it gives me good load density and velocity, I'm not going to write it off because it might be a little more unstable than Retumbo. I'll do my part to make it work and make the adjustments when needed.

http://www.longrangehunting.com/forums/f17/338-allen-xpress-rl33-load-development-120353/

Alright, you got me. I'm gonna order some. After reading Kirby's article and the vast velocity improvement he discovered I've got to try it. Hopefully it's not as wild as RL22. With my seating depth RL33 should give me close to 100% load density. I do have a function in my 'shooter' program for correction of powder temp change.

 

[MontanaRifleman]

I think it's worth at least a try. Get a pound to start with and work up a load in warm/hot weather. That way if there is a temp diff it will be for the cooler. RL33 and 17 is different chemistry than the other Reloader powders. I think they're a little more stable but 100% sure.

Work up a load with each Retumbo and RL33 in hot weather then test them in cooler weather and check the differences of each. There may not be a big diff.

And now I'm reading of other guys in other threads having issues with Retumbo. Mostly from compressed loads. I've never had any issues it, but apparently some are.

 

[Tumbleweed]

OK, so I finally got my 2lbs of RL33 today after nearly two weeks waiting on shipping. I loaded up 6 rounds for a pressure test moving up in 1 grain increments. Sun was out bright and at a weird angle to the chronograph, so I don't put too much stock in the accuracy of the readings yet. Here are the results:

98.0 3,065 no pressure
99.0 3,086 no pressure
100.0 3,152 tiny swipe mark from extractor hole
101.0 3,137 very minor swipe mark from extractor hole
102.0 3,244 swipe mark with visual circle in case head from extractor hole
103.0 3,267 swipe mark and very, very slightly raised circle from extractor hole

I decided that 103 would be a max (go no farther) load. The 103 load was on a separate target from the below target. Bolt lift was never sticky and primer pocket remained tight at 103.
I have three rounds loaded at 102 that I will chronograph and shoot at 275 yards in the morning before the sun jacks with the chronograph readings. So far I am impressed with the numbers as the best I could do with Retumbo at the same pressure levels was about 3,080fps.

 

[AZShooter]

Tumbleweed,

Glad to see you tried RL-33. I had similar results with my 300 RUM. I had no data to reference well over a year ago. I worked up to 102 grs with Berger's 230 hybrid and had a bit of bolt lift and shiny spot on case head.

Best accuracy was with 100 gr for a velocity of 2975 fps. This is with a 24" 300 RUM. I know, I know, why such a short barrel? I JUST had to try the 230s and didn't have a fast enough twist on my 27" original Rum barrel. I took a 300 win mag rem takeoff and rechambered it myself. It is so accurate and handy with its short barrel it is staying on the rifle.

Hope RL-33 works out for you. Keep up the reporting.

Ross

 

[MontanaRifleman]

Interested to see what velocities you're coming up with.

 

[Tumbleweed]

Well, I set up the chronograph this early this morning and fired three rounds of 102 grains. Unfortunately I did not get a reading on any of the shots. I guess I was a little early and did not have enough light. Having to get this done before taking the kids to school put a time crunch on things. 2 shots at 275 yards were .75" apart with the other up slightly making the group 2.25". Not fabulous but I will play a little more witht the 102 load and make sure to get speed readings next time. With a 100 yard zero and input velocity of 3240, shooter called for 2.0MOA at 275 yards. My group center was near perfectly centered with my POA. This tells me that I have to be above 3200fps.

 

[MontanaRifleman]

Well, I set up the chronograph this early this morning and fired three rounds of 102 grains. Unfortunately I did not get a reading on any of the shots. I guess I was a little early and did not have enough light. Having to get this done before taking the kids to school put a time crunch on things. 2 shots at 275 yards were .75" apart with the other up slightly making the group 2.25". Not fabulous but I will play a little more witht the 102 load and make sure to get speed readings next time. With a 100 yard zero and input velocity of 3240, shooter called for 2.0MOA at 275 yards. My group center was near perfectly centered with my POA. This tells me that I have to be above 3200fps.

Time to invest in a Magnetospeed

 

[Tumbleweed]

Time to invest in a Magnetospeed

I like the idea behind them eliminating all of the lighting issues. However I understand they will change point of impact and possibly grouping.. With barrel life and component costs/shortages to consider, I always collect target data at the same time when I chronograph.

 

[MontanaRifleman]

I like the idea behind them eliminating all of the lighting issues. However I understand they will change point of impact and possibly grouping.. With barrel life and component costs/shortages to consider, I always collect target data at the same time when I chronograph.

Most of what I have read on them says they have very little to no affect on groups and have little affect on POI if any. A lot of guys are using with good results. They may even actually save you barrel life, gas and time by giving you good info in any condnitions so you don't have to make multiple trips to the range. Once you have a good load you like, in 3 to 5 shots you can get an accurate velocity range and not have to bother with it anymore. I'll be getting one before too long.

 

[Lefty7mmstw]

I like the idea behind them eliminating all of the lighting issues. However I understand they will change point of impact and possibly grouping.. With barrel life and component costs/shortages to consider, I always collect target data at the same time when I chronograph.

That's precisely the reason we gave up my the chrono's my father built years ago; he was building chrono's before the optical ones were really available. They used two laminated foil plates and Dad built/ programmed the electronics to measure the time between plates and arrive at a speed. They were accurate and had great shot to shot consistancy due to the way he built the stand, but you couldn't see a downrange target through the foil plates so you shot for speed/uniformity then for group. The plates also had to be replaced every dozen shots or so so if you were doing a bunch of stuff you may have to be chrono'ing for a while if the range was busy.

 

[Tumbleweed]

Well, I got out and began shooting 3 shot groups starting with 102 grains RL33. I also sent a group at 103 and 104 grains. I had good conditions for the chronograph to perform well. The groups were shot at 275 yards and ranged from 2"-3". I noticed that velocity did not improve over 102 grains as the barrel simply couldn't burn any more powder. 104 ended up being a max safe load. Velocities with all three loads averaged around 3250fps. Accuracy was obviously not good enough as I'm looking for .5MOA or under. Here's the awesome thing, I backed down to 101.5 and groups calmed right down but the velocity stayed at 3240fps average. No pressure signs at all on the case head. The 275 yard group measured 1.125" with two in the same hole. I took it out this morning to shoot 700 yards before the wind picked up. I had a very slightly shifting 1mph wind. The 700 yard group measures 4.5" and vertical spread measures a whopping .375". The shifting wind could have easily moved the left bullet out of the group. I'm settling on this load.

275 Yard Group

700 Yard Group

 

[MontanaRifleman]

Great! That stokes me up for some RL33 load development!

 

[Hired Gun]

Mighty fine shooting for a 10 power scope.