Tried RL-33 in three different chamberings today


Well-Known Member
Dec 12, 2005
Tucson Az
There is little data to reference at this point. Determined by comparisons and now by testing that RL-33 is slower than Retumbo for the 7 Rem Mag, 257 weatherby and 6mm-284.

With all three rifles didn't make any changes other than switching powder. Used the same brass, primers, bullets, seating depth, neck tension etc.


7 Rem Mag: 24" Rem barrel, moly coated 162 A-max seated .010" into rifling.

Original load: 72 gr of Retumbo 2975 fps

starting load 76 gr vel 2837
Unfortunately the chrono had to be adjusted, shot without it till they had a ceasefire.
worked up to 79 gr for vel of 3000 for very small gain over Retumbo
80 grs showed a hint of lift and a small shiny spot on casehead.

I used a bullet seating comparitor and noticed that even with the use of a drop tube the powder was filling the case. 79 gr and up caused the OAL to lengthen over .010", enough so the bullet wouldn't fit into magazine.

I can see why Alliant only mentioned a load for the 175 gr bullet.
257 Weatherby: 28" #5 fluted SS Lilja 3 groove barrel, moly coated 110 accubond, .015" off rifling.

Original load 75.5 gr of RL-25 vel 3615 fps

starting load 76 gr for vel of 3318
jumped to 80 gr 3432 fps
81 gr 3525
82 gr 3559

No signs of pressure what so ever. There is still some room for powder, will be trying that in the future.
6mm-284: 28" SS Bartlein 5R barrel 1 in 7.5 twist

Original load: 58 gr of Retumbo, 105 Berger target hybrid seated .065" off rifling vel 3307 fps

starting load 58 gr vel 3074
jumped to 61 grs vel 3274
62 grs vel 3335

No signs of pressure, believe can add more powder.

Now for the most interesting part: I didn't pay much attention to the 7 mag as I shot at different targets. Afterwards I saw the POI was almost identical. Hmmm that's interesting I thought.

With the 257 Roy and the 6mm-284 I shot at the same target for each rifle. In both cases the bullets went to the same POI! The Roy made a nice 1/2" cluster at 100 yds. The 6mm-284 with one bullet lumbering along at 3074 and the upper end loads to 3335 shot a very tiny cluster with several in the exact same hole! In my 30 plus years of handloading I have never seen this happen. I would say one rifle doing this is just a rare event. To see three rifles do this, it isn't a coincidence.

I won't be shooting for several days. I want to continue with the 257 and the 6mm-284 to see what happens first, pressure or running out of powder space. I'll report back soon.
Thank you for sharing this information. Have looked at different reviews on RL-33 will give it a try in the near future......
10-7-2012 Continuing with RL-33:

257 Weatherby moly 110 accubond:

83 3625 which slightly faster than old load with RL-25
83.5 3674 fps shot well two shots were same velocity
84 gr 3704 fps shot well two shots were same velocity
84.5 gr 3735 slight signs of pressure on one case of four this is max case capacity with drop tube

This makes a 91 fps gain over a max load of RL-25

6mm-284 non moly Berger target hybrid

worked up to 64.5 gr which showed slight lift with very tiny shiny spot on case head from Rem 700's ejector hole. (This is with 8 times fired lapua brass)

62.5 gr 3376
63 gr 3414
63.5 gr 3453
64 gr 3485 fps excellent accuracy
64.5 gr 3535 a bit warm max case capacity using drop tube

Old velocity with Retumbo was 3307 which was the highest charge of powder without pressure issues. RL-33 yielded a 178 fps increase!

I will be replacing the 6mm-284 load if it continues to work well in the next few shooting sessions. Ditto for the 257.

I look forward to hearing on what others get with similar over bore cases like the 7 RUM, 257 STW, 6.5-300 weatherby, and many of Kirby's magnums.
You are welcome. Glad to share what I have found. I waited a long time to try this powder. I think it can be stated as fact it is slower than Retumbo.

I hope some one with a 7 RUM can share soon.
I shoot a 6x284 with 30" 8" twist bbl. What primers ? I wonder if a magnum primer might help ? So should I start at 62grs pushing a 107 sierra MK ?
Summarizing all components: Berger 105 target hybrid, Lapua 6.5-284 brass and Fed 210 match primer. The OAL is 2.975" to fit and feed from Wyatt's mag box. Jump to rifling is .065"

I would think 60-62 gr for starting and work up to what your rifle prefers.

When I was researching this build I would save any information on the 6mm-284 in my documents. I just ran back throught the pages and never read of anyone using a mag primer.
maybe someone can educate me. I just dont see the reasoning for using powders that burn that slowly in cases that size. Maybe if i were loading a 378 wby necked down to .25 cal. For the most part something like 4831 will get you anywhere using less powder and certianly nothing slower then 7828 or re25 is called for in a case that size with ANY bullet weight and even re25 is borderline to slow for all but the heaviest projectiles. If someone gave me some for free i might try it but powders expensive and i just dont see any use in trying ineffiecent combos that buy you nothing. Let alone adding more and more powders to the allready large selection in the cabinet now. Im not trying to be sarcastic in anyway or stomp on your post. Id just like to here the reasoning.
I'll give your question a try. First of all RL-33 is only the second of a line of unique powders offered by Alliant. Borrowed this line from an ad: "New Reloder 33 Delivers More Speed in Big Magnums
Now Alliant is introducing a new powder, Reloder 33, that uses the same kernel-impregnation technology first pioneered in Reloder 17. Alliant Reloder 33 is a new powder created by Rheinmetall Nitrochemie.

Many of us were stunned at the higher velocities we obtained with RL-17 in mid sized cases. When they announced RL-33 would soon be available earlier this year many of us were very interested.

You said: "For the most part something like 4831 will get you anywhere using less powder and certainly nothing slower then 7828 or re25 is called for..."

RL-33 WILL get us somewhere the other powders cannot do, MORE VELOCITY! Remember this site is LONG RANGE HUNTING where hunters strive for more performance regardless of the costs. If we can get more velocity then there is less wind drift and more retained energy at long distances.

I would argue that just because a case is full that it is not worth using. Many of the very best powders are close to 100% load density or in some cases slightly over that amount and compressed. I don't think that RL-33 can be called inefficient IF it delivers more velocity.

Sure the 7 Rem Mag didn't produce any gains but the limited load data that Alliant has shared only had the 175 gr bullet listed. My trial proved that it isn't the best powder for this particular case with lighter bullets.

On the flipside the 6mm-284's velocity with RL-33 increased to velocities that I was unable to obtain in this particular rifle. Sure I had read that a few guys were getting close to 3500 fps with RL-22 and the 107 sierra. Even when I had a 30" 6mm-284 I couldn't do it. To get close to 3500 with a 28" barrel now that is something.

The 257 Weatherby I tested was no slouch either. It gained 90 fps over the maxed out load of RL-25.

There was something else that I mentioned in the first post, the powder seems to throw many of the rounds into the same POI as the charge weight was progressively increased. In the second session where I added more powder the groups finally moved slightly with each higher charge weight. BUT many of the charge weights had little or no velocity differences. Twice I had two shots with identical velocities in different charge weights. It says to me that the combination of heavy bullet and powder charge are a good combination. Consistency shot to shot helps to keep group size tight at long range. I saw the same consistency with RL-17 in a 338 RCM with a heavy bullet.

I will say that I didn't expect RL-33 to be this slow. I had hopes that it would be similar to RL-25 or maybe H1000 and not slower than Retumbo. There is no doubt I will be using it in the 257 Weatherby and 6mm-284 as no other powder can produce those velocities in my rifles. I think it is up to the individual to decide what powder suits them. I have plans to make a 7 RUM in the next year with enough twist to work with the upcoming 195 Berger. I believe it will work very well in that package.

So to summarize you are right to question using RL-33. The answer is more performance.
Im not beyond fooling with new powders myself. Just dont do as much of it as i used to. To many other loading projects to take up my time. I did load a bunch this last summer using re17. I found it to be a bit overated myself. Most of my guns didnt like it for accuracy. About all of them did better with 15 on the faster side and 19 on the slower. Velocity gains were there in some loads but not all. Only round it really seemed to shine in was when working up loads for my buddys 300 wsm. It gave a true 100 fps better velocity then anything else we tried and did give great accuracy in that round. I have to wonder though if alliant isnt posting load data for 17 thats a bit hotter then they do for the others just to push there more velocity theroy. It seemed to get hot real fast if you loaded any hotter then there data and with 19 theres a good cushion in most guns. I guess i understand trying to get the most out of your cartridge but most of my use is 500 yard and less deer hunting and even a 100 fps in a 257 wby means about absolutely nothing for that purpose. Accuracy is what i look for in a load FIRST. By accuracy I not only mean group size but consistancy. The first round has to go cold where at least the next three do and when i shoot groups i shoot 5 shot groups usually and average at least 3 5 shot groups to test a powder bullet combo. Ive just seen to many times where a 3 shot 1/2 inch group one day turned into a 2 inch 5 shot group the next. If i can get consistant one inch groups with a load it sure beats the heck out of an occasional 1/2 group or gaining a 100 fps. Now if you can get the best of all worlds and get absoulte max velocity and absoulte max accuaracy out of the same load thats fantastic. But ive found in the real world that happens about as much as getting struck by lightening. By the way in my experience when you get the same velocitys out of two differnt powder charges it usually means youve pushed that powder past its effiecent pressure. What it shows is the extra powder either isnt burning or you at least need some more barrel lenght . you will see that alot in mag handgun loads using slow ball powder like 110 or lilgun. You will get to the point that adding more powder will even decrease velocity.Im no chemist or sceintist and cant give you theroy, just my own personal experience. Like i said im no paper puncher for the most part either. I kill deer. Lots of deer. 62 so far this yearand it was a slow year. I do have a pretty good grasp as to how differnt bullets, velocitys and various calibers put down deer. I do like mag rifles for long range deer hunting so velocity does matter to me but believe me at even 500 yards the differnce in the velocity of a 2506 and a 257 wby with the same exact bullet means less then bullet placement that 3 inchs to one side of the other when it comes to putting them dead on the spot.
Alliant responded to my message of where to buy by saying their shipping to distributors. I hate to have to pay that $25 haz mat fee...... Any way I shoot a 6x284 and am really looking forward to burning this stuff.
Anyone done any temperature/velocity testing? Did I miss that? If it isn't fairly temp insensitive, I don't care how much faster it may be.

I thought when I wrote that one description that it might be interpreted incorrectly. I have experienced two different powder charges showing similar velocities which means you have maxed out the velocity. This is NOT what I was describing. In my testing I shot four rounds with each charge weight noting velocites. This happened twice: when shooting with the same charge weight I had two of the four rounds register the same velocity. When shooting with one more grain of powder I also had two of the four rounds fired with same velocities.

I will agree that RL-17 works with a limited number of cases. I also agree that the 300 WSM is one of them. So is the 284 win, 6mm Rem, and even the 338 RCM. It would appear the midsized cases thrive on this powder.

It is apparent that RL-33 has limited applications as well.

Regarding Alliant listing loads that make RL-17 appear to surpass other powders...that is not the case. RL-17 IS a longer burning curve powder. Just look at what Bob Jensen and German Salazar found with a Oehler 43 equipped for pressure-testing: Alliant Reloder 17
These powder made by Nitro Chemie ARE different.

I envy your being able to shoot more deer than I can with jackrabbits and coyotes.

Have to run....
AZshooter; thanks for the info and I will be looking for the powder to try in my 257 plus a similar 6-06. Can you suggest a starting load for 95 grain loads in the 6-284. Thanks again. Dave