I found out that I am going to get some Alliant RL-15.5 for Christmas! I do not REALLY know this powder. I read it's burn rate is between RL-15 and RL-16. What does that actually mean? Is it CLOSER to RL-16 OR RL-15. I do know Varget and RL-15 are just about tit-for-tat. I know that RL-16 is just about like a faster lot of H4350. I am currently building a load in a new 6.5 x 47 barrel with Berger 144s and H4350. I was just wondering if anyone has any experience with this powder in a 6.5 x 47 Lapua and at least a 140 class bullet. Any info would be greatly appreciated. And if you have a good handle on it's realistic burn rate. I do NOT trust "burn rate charts" at all.... Thank You in advance!....
RL-15.5 in the 6.5 x 47 Lapua.... Any ideas on a load?
- Thread starter ShootDots
- Start date
Ben, I load this powder in the 6.5x47. It is noticeably slower than Varget. I recommend starting your work-up at the upper end of Varget charges and work up from there. I'd start around 36.5 grains of RL-15.5. I'm sure you'll find something in short order. You'll get some very good velocity out of this powder.
Edited to add - If you have a Dasher/BRX/BRDX lying around, try it in the 6mms. You can thank me later.
Edited to add - If you have a Dasher/BRX/BRDX lying around, try it in the 6mms. You can thank me later.
I am also "considering" it in my 6 Creed with 109 Bergers. I am "guessing" that "somewhere" in the close vicinity of 38 +/- with the 144s might really be good. With 39.6grs of H4350 and the 144s, I am getting 2815 thereabouts. I have a 32" barrel. I wonder where I could start in the 6 Creed with those 109s? Any idea?
I don't have a 6mm Creedmoor, but I do load it in a 6XC. The Creedmoor has a bit more capacity than the XC, so I can get you in the ballpark on that one. I've not loaded 109s in the XC, but I have data on the 110 SMKs and the 108 Bergers. I'll check my notes and get back to you shortly.
FWIW, I prefer RL-16 in the big sixes.
Ben, I ran a powder ladder up to 39.0 gr of RL-15.5 with a 108 Berger in the 6mm XC, stopping there. My notes indicate an ejector mark at that charge. The charge ultimately settled on was 38.4 gr. with the 108. That charge should be fine out of your Creedmoor with a 109, which has substantially less bearing surface than the 108.
My pleasure!
Mine liked 38.4gns in a Peterson or Lapua case (same volume), Vapor Trail 133gn, and a CCI 450.
RL15.5 is just a tiny bit faster than H4350. Same speed is 38.8gns of H4350 and 39.3gns of RL16.
The barrel that liked RL15.5 didn’t like the 153.5 or 144. The barrel that liked the 153.5 best really liked RL16. And my current barrel likes the 144 with H4350.
RL15.5 is just a tiny bit faster than H4350. Same speed is 38.8gns of H4350 and 39.3gns of RL16.
The barrel that liked RL15.5 didn’t like the 153.5 or 144. The barrel that liked the 153.5 best really liked RL16. And my current barrel likes the 144 with H4350.
That is valuable info >>> Thanks much!
Right now, I am using 39.6grs of H4350 with the 144s and getting 2815ish.. My barrel loves the 144s and it likes H4350 >>> accuracy is great but ES.s are running 15-18f.p.s. I am going to run a primer test with CCI BR-4s, CCI-450s, Fed 205s and Rem 7-1/2BRs.. Maybe that will tighten the ESs a bit...But in either event, I want to try RL-15.5 with the 144s to see what may happen.. Thanks again..
RL15.5 is a really easy-going powder that builds pressure smoothly without surprises. I most recently used it in a 22BR shooting 90SMK and I was able to go 100fps faster than Varget or H4350 without any ill effects beyond wearing out the barrel in 1200 rnds instead of the more usual 1600. I think it is a great powder and if the price comes back down in alignment with Vihtavouri, I would buy more.
shoot4fun
Gold $$ Contributor
RL16 is a clear winner for the 6 Creedmoor.
I'm glad you started this thread because I'm getting geared up to shoot the 6.5-47L more in 2026 and wanted to use 15.5. I have quite a lot of it and it seems (to me) better than Varget as far as accuracy and temperature sensitivity.
taylorw
Gold $$ Contributor
Did some pressure testing a couple of years back with a 6.5 creed. Not a 1:1 comparison but might be useful to compare burn rates between different powders. I ended up settling on 40.3 grains of 15.5 in this rifle, after shooting at distance
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That is excellent info! Thank You!
I am using N555 in my 6 Creed... So far I am quite impressed! W-A-Y back some years ago, while shooting at my THEN home range at Bayou Rifles, I finally got my L/R High Master card! It was done with a 6.5 x 47 Lapua and Berger 140 Hybrids. I am returning to the "old" 6.5 x 47 with great desire!
In one of Clint Eastwood's movies he had a profound proverb. "A man has got to know his limitations!" Since I am aging and have moved to Tennessee, I shoot only once per month. Maybe twice a year we shoot a 600 and a 1000 in the same month. My skills are WAY down. However, my love for shooting has not waned. So, I have to recognize my "limitations" and be happy in those parameters. Hence my getting away from the .300 WSM boomers and the return to smaller calibers as they make shooting fun again! I have a very difficult time winning now a days, so getting pounded by big cartridges is not helping my win percentage >>>just punishing me for nothing! The 6mms, 6.5mm and possibly the 25 Creed in coming years makes shooting fun again! They are easy to shoot, extremely accurate and so far I am doing at least as good with them as with the BOOMERS!
SilhouetteShooter
Gold $$ Contributor
I have been using it for a few years in a 6.5-47L
I have one barrel that loves 37.9 with a 140 hybrid, v2800, ES is single digit
I loaded it with 35.9 (not on purpose but to lazy to pull them) and the velocity dropped to V2695, however it shot very well. So I used them in a match.
Point is, it’s very forgiving powder.
Give it a try
I have one barrel that loves 37.9 with a 140 hybrid, v2800, ES is single digit
I loaded it with 35.9 (not on purpose but to lazy to pull them) and the velocity dropped to V2695, however it shot very well. So I used them in a match.
Point is, it’s very forgiving powder.
Give it a try
T-Rust me..... I will give it a good run!
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