I just got the Quickload update and playing around with RL-26 yields some very interest results. According to Quickload:

87.0 gr in .375 H&H supposedly pushes a 300 gr partition at 2750+ fps out of a 24" barrel (89.5 gr in .375 Ruger does the same)

94.5 gr in .375 Wby. supposedly pushes a 300 gr Partition at 2850+ fps out of a 24" barrel (even with a 3.56" OAL) within SAAMI pressures limits

94.0 gr in .416 Rem. pushes a 400 gr partition at 2587 fps out of a 24" barrel (3.60" OAL) at 62k psi

Granted, all of these loads are fairly compressed (~110%) and Quickload is obviously not gospel Truth. But the results are intriguing none the less, especially since even a 100 fps over-estimation on the part of Quickload would still lead to some fairly hot loads. It is also worth noting that RL-26 made in Switzerland (not Bofors) like RL-17 and is also supposedly temperature resistant. It also supposedly has some anti-copper fouling agent.

Unfortunately, I haven't been able to locate any RL-26 as of yet.

Have any of you tried Rl-26 yet in a .375 of some variety? In any other calibers?

Do any of you know of anywhere that has RL-26 in stock?

I am surprised that a powder as slow as Rel26 is intended to be, could produce such hot loads in the Quickload program. It would be expected that Rel 17 would do higher velocities in the 375H&H.

What you need to do is load up some rounds and shoot them over a chronograph. I will go out on a limb and guess that there will be a 150fps drop in velocity, though it would be great if this guess is wrong.

PS:
I just checked the Alliant website. for 270win and 150 grain bullets they are recommending 60 grains of Rel 26 for over 3000fps (hot for a 270Win with 150gn), so Rel 26 is apparently very slow and also very dense, allowing a lot of powder to be packed in the case.

You can pack cases full and compress RE 26, 17,etc, even in my 585HE

and get more speed at lower peak pressures than RE25 or 22, less case expansion.

Its overall mean barrel pressure, MBP, is higher due to a longer averaged out,

taller pressure curve that RE25-22, due to the new powder technology

used with it and RE17, Re33, Re50. where the deterrent is all through the powder,

rather than on the ,004" thick surface. So you pack in more of slower

powder by comparison, and gets a longer taller curve.more speed.. Ed

In my 375 AI and 416 RUM, QL is not good at predicting velocities and PSIs with the super slow powders. In reality with the super slow powder I can't bring the PSI up to ~60,000 PSI and get the predicted high velocities.

Also, marked powder compression in over-bore cartridges will often cause the case to expand, thus preventing chambering. To avoid this problem, I try to minimize powder compression as much as possible.

For these over-bore (I really mean under bore - sorry, my bad) cartridges, QL is much better with predictions using Re17, 4350, and faster powders.

quote:

Originally posted by Ackley Improved User:
In my 375 AI and 416 RUM, QL is not good at predicting velocities and PSIs with the super slow powders. In reality with the super slow powder I can't bring the PSI up to ~60,000 PSI and get the predicted high velocities.

Also, marked powder compression in over-bore cartridges will often cause the case to expand, thus preventing chambering. To avoid this problem, I try to minimize powder compression as much as possible.

For these over-bore cartridges, QL is much better with predictions using Re17, 4350, and faster powders.

Yes, this underlines the need for real world testing, beyond the Quickload prediction.

One quibble: I would not call either the 375 AI, 375H&H, or the 416 RUM "overbore," unless by that you simply mean "bottleneck cartridge." As diameter widens and projectiles get heavier, a cartridge needs more powder in order to maintain velocities that simply approach or keep up with smaller diameter cartridges. Even the 416Rigby is not "overbore" but nicely balanced to be a long-range round when handloaded to 60k psi. When a cartridge loses or barely maintains velocity when going from IMR 4350 to H4831, then practically speaking it is not overbore. Take a look at the 30-06 and magnify it in your imagination. It ends up with more "overbore" bottleneck than the 416Rigby.

quote:

One quibble: I would not call either the 375 AI, 375H&H, or the 416 RUM "overbore," unless by that you simply mean "bottleneck cartridge." As diameter widens and projectiles get heavier, a cartridge needs more powder in order to maintain velocities that simply approach or keep up with smaller diameter cartridges. Even the 416Rigby is not "overbore" but nicely balanced to be a long-range round when handloaded to 60k psi. When a cartridge loses or barely maintains velocity when going from IMR 4350 to H4831, then practically speaking it is not overbore. Take a look at the 30-06 and magnify it in your imagination. It ends up with more "overbore" bottleneck than the 416Rigby.

I agree - my bad - I meant under-bore but typed over-bore, under-bore meaning relatively large diameter caliber compared to case capacity - opposite of an over-bore cartridge such as the 300 RUM.

Also, I've been reloading Re26 ("slower burning version of Re17"), which seems to have burn-rate more akin to Re22 than Re25. I load a lot of Re25 and Re26 is faster burning. Moreover, IMR 7797 seems faster than advertised with a burn rate more akin to Re22.

These two powders might work well with heavy for caliber bullets in my 375 AI (i.e., 350 gr Woodleigh) or 416 RUM (i.e., 430 gr NFSS or 450 Woodleigh RN or FMJ). I haven't tried yet.

Re26 is giving me great velocities in my 300 WM using 190 gr LR Accubonds at 3200 fps (26" barrel).

I plan on trying these two powders in my 338 RUM, but Re33 may be hard to beat.

IMO, they would be worth trying in a 338 WM or 416 Rigby, especially Re26.

I the lab bomb tests, RE26 is slower than RE25-22,

but its new technology allows a longer taller, overall

average higher pressurea curve. thus mean barrel pressure

is higher. Factory doesn't test speed of bullets, they test

speed of ignition to peak pressure. If a powder gets peak pressure

at 80 milli-seconds it is considered faster, than one getting to

peak pressure at 90 ms, even if the slower one takes 10 inches of

barrel to drop half the pressure compared to faster one dropping

half the pressure in 6 inches. But slower one dropping pressure

slower will get bullet out faster.Ed

Thanks, Ed.

I understand the physics of pressure curves and converting the area under a graph into velocity~energy. The other constraint that is not yet clear is whether a slower powder can reach the cartridge's max pressure. For example, a cartridge that is balanced just right when stuffed with IMR 4350 will hit its peak pressure and produce a particular velocity. Let's say it hits 3000fps with a 62k peak. If H4831 is equally stuffed in that cartridge it will achieve less than max pressure and velocity, let's say 2950fps.

theoretically, if the pressure curve is stretched out long enough, the slower powder will reach and surpass the 4350 velocity in that example cartridge. However, that is a lot of streching and tests need to be run to see if it really stretches so far in the real world.

Reloder 17 itself is said to be such a miracle powder, and it is quite good, but the streching of the curve is only so much and velocities typically seem about a 50-100fps improvement. Of course, I happen to like a 100fps improvement.

So do I and in all rifle cases averaged out, they have about 4% gain

in velocity and 8% in energy, and good deal, it is easier

on cases also. More speed and more case life with

my 585, and in brass shotgun cases with RE17.Ed

I found some RL-26 and did an initial ladder test in my .375 RUM with 250 gr TTSX today.

In theory, RL-26 is a bit slow for lighter bullets and would be better suited to 300s or 350s, but QL shows 100% burn and a nice load density so I thought I'd give it a go.

From 97.5 gr through 103.0 gr of RL-26, my chrono was giving me ~100 fps less than Quickload was predicting. For what it's worth, my chrono was giving me ~80 fps less than the Quickload prediction for Norma MRP (from 96.5 gr to 100.0 gr).

I plan to shoot some groups on Wed. and will post results.