RL-17 consistency
- Thread starter logan1080
- Start date
I hope not. It was a suggested powder for me to try in my short barrel 308. I don't want a powder that is gonna be really temperamental. Having to carry many drop charts based on slight temperature changes would not be ideal.
Never mind, beat me to it.
Rel17 is very consistent. It really helps to use magnum primers with it as well. Another poweder that works well and IMHO is every bit as good, though not any better is W748, of course, with magnum primeres again.
Chinbullco
Regular
- Location
- NW Alberta
Have you been shooting over your chronograph at -30C again?
Yep! We use them all winter long up here, both the Oehlers and the Chronys. River Rat uses his ProChrono, as well. When we were doing the 308 load development for Bison hunting last winter, we purposely did it at -20 and colder, because that is the temps we hunt them at.
The trick, of course, is to keep the battery warm. I do it by keeping it in my shirt pocket until we actually need it, then connecting it just before we shoot. When we are done a string, back in the pocket it goes until the next string of shots. It only takes a few seconds to connect or disconnect the battery in a Chrony, a bit longer in the other units.
If you leave the batteries in the unit they will last about twenty minutes at -30, and are no go until you get them warmed up again.
Ted
The trick, of course, is to keep the battery warm. I do it by keeping it in my shirt pocket until we actually need it, then connecting it just before we shoot. When we are done a string, back in the pocket it goes until the next string of shots. It only takes a few seconds to connect or disconnect the battery in a Chrony, a bit longer in the other units.
If you leave the batteries in the unit they will last about twenty minutes at -30, and are no go until you get them warmed up again.
Ted
Northman999
CGN Ultra frequent flyer
- Location
- Southern Yukon
That RL-17 is just a great powder IMO. I've been impressed with it in every cartidge I've tried and both in summer and winter temperatures.
Chinbullco
Regular
- Location
- NW Alberta
-30c chronogragh
So how close are identical loads from 20C to -30C in a 308? Do you have any examples of extreme velocity spread with a particular powder in any cartridge?
I did a temperature test with the stuff with both regular and magnum primers where I too three batches of loaded ammo. On batch I put in the freezer of the club house, one I sat on the shooting bench in open air, the other went in a cooler inside of an electric heating blanket that was between two pieces of foam that took up most of the space in the cooler. Each batch of ammo was soaked for at least two hours before firing.
When it came to firing, the ammo was shot in a round robin sequence, waiting one minute in between shots. That is to say: fire cold round, wait 1 min., fire room temp. round, wait 1 min., fire hot round, wait one minute, fire cold round, wait 1 min., fire room temp. round, wait 1 min., fire hot round, etc...
Rounds where fired as quickly as they could be taken from their cold/room/hot storage loaded. loaded into the rifle and shot through the chronograph. So there was minimal change in temperature due to contact with the the chamber.
The barrel had a pressure system attached to it as well. I wouldn't recommend using that high of a hot temperature without one. When I did this with RL-25, it changed so much I was proof testing the gun.
RL-17 results looked like this:
By contrast, results with Varget looked like this:
Here is what an old IMR powder looks like, for comparison:
The number in front of the 'x' is the slope of the curve, it represents the rate of change in fps. per degree F (bottom axis).
RL-17 does not have very impressive temperature stability, sorry. Some of the F-Class shooters have different loads developed with it for different temperature ranges to deal with this.
When it came to firing, the ammo was shot in a round robin sequence, waiting one minute in between shots. That is to say: fire cold round, wait 1 min., fire room temp. round, wait 1 min., fire hot round, wait one minute, fire cold round, wait 1 min., fire room temp. round, wait 1 min., fire hot round, etc...
Rounds where fired as quickly as they could be taken from their cold/room/hot storage loaded. loaded into the rifle and shot through the chronograph. So there was minimal change in temperature due to contact with the the chamber.
The barrel had a pressure system attached to it as well. I wouldn't recommend using that high of a hot temperature without one. When I did this with RL-25, it changed so much I was proof testing the gun.
RL-17 results looked like this:
By contrast, results with Varget looked like this:
Here is what an old IMR powder looks like, for comparison:
The number in front of the 'x' is the slope of the curve, it represents the rate of change in fps. per degree F (bottom axis).
RL-17 does not have very impressive temperature stability, sorry. Some of the F-Class shooters have different loads developed with it for different temperature ranges to deal with this.
lineofsight
CGN frequent flyer
- Location
- Lower Mainland, BC
Tagged - good to see data in support of discussion, thanks.
Chinbullco,
We shoot all winter, but the only powders we tested at extreme low temps were Re17 and H4350. They were remarkably similar, with Re 17 having the least spread. I am away at the moment and notes are at home, but IIRC, Re17 showed considerably less than 100 fps difference, from -30 to +20C, something on the order of around 2600 fps at -30, and less than 2700 at +20 with 180s. I actually started a thread sometime back about this. http://www.canadiangunnutz.com/forum/showthread.php?t=403201
I remember for sure that the difference in point of impact was less than an inch at 100 yd between the two temperatures, because we made no change in zero for bear hunting last Spring.
Ted
Hi Folks,
Something to add.
I have a TC Icon 30-06. Worked up an RL-17 load this summer. 180 gn sierra pro hunter on top of 55.5 gn RL-17, win LR mag primer. Muzzle vel. 2800 fps. As I remember, it was something like 20-25C when I zeroed it
At the end of october, the POI dropped by a little over an inch at 100 yards. I re-zeroed. Temp was about 7C
Shot a doe last weekend, impact was lower than i expected.
I rechecked the load/rifle and this is what I found today
temp = -9C, no wind, overcast
100 yd - 3 shots - 0.5" high, average muzzle vel ~ 2740
200 yd - shots - 2.5" low
I usually regard chrony numbers as 'ballpark' kinda figures, but I still kept the battery in my pocket until I needed it - to minimize measurement error.
Group size (only 3 shots) at 200 is just over 1" - this is slightly better than what I was getting in the summer - so I think the possibility of some sort of mechanical failure in the rifle (which is what my buddy suggested) is pretty much ruled out. Could've knocked it I suppose - but I'm pretty careful with my guns - I think I would have remembered dropping it or something like that.
Anyway, the POI definitely changed - almost a perfect vertical drop. Don't think I can blame all of that drop on loss of muzzle velocity, but it will be worth doping this out for next season.
This seems like similar results to those found here:
http://longrangeshooter.com/2009/02/temperature-effects-on-zero/
I was going to work up an H4350 load anyway, now I will just have to check it for POI variation over temperature
Fat
Fat
Something to add.
I have a TC Icon 30-06. Worked up an RL-17 load this summer. 180 gn sierra pro hunter on top of 55.5 gn RL-17, win LR mag primer. Muzzle vel. 2800 fps. As I remember, it was something like 20-25C when I zeroed it
At the end of october, the POI dropped by a little over an inch at 100 yards. I re-zeroed. Temp was about 7C
Shot a doe last weekend, impact was lower than i expected.
I rechecked the load/rifle and this is what I found today
temp = -9C, no wind, overcast
100 yd - 3 shots - 0.5" high, average muzzle vel ~ 2740
200 yd - shots - 2.5" low
I usually regard chrony numbers as 'ballpark' kinda figures, but I still kept the battery in my pocket until I needed it - to minimize measurement error.
Group size (only 3 shots) at 200 is just over 1" - this is slightly better than what I was getting in the summer - so I think the possibility of some sort of mechanical failure in the rifle (which is what my buddy suggested) is pretty much ruled out. Could've knocked it I suppose - but I'm pretty careful with my guns - I think I would have remembered dropping it or something like that.
Anyway, the POI definitely changed - almost a perfect vertical drop. Don't think I can blame all of that drop on loss of muzzle velocity, but it will be worth doping this out for next season.
This seems like similar results to those found here:
http://longrangeshooter.com/2009/02/temperature-effects-on-zero/
I was going to work up an H4350 load anyway, now I will just have to check it for POI variation over temperature
Fat
Fat
