RL-17 vs H4350 and temperature variance

[toddconley]

I was a huge RL 17 fan. The velocitys were awsome. Gun shot great. Presures were fine. Then I show up at a May match with temps in 100s. Couldn't open my bolt and almost shot over a berm @ 750 yds. Took myself out of the match for safety. I will not shoot it ever again in my match rifle. I probably will in some of my hunting guns but not ever again in a match rifle. I am now shooting 4350 almost 100%.
My 2cents
Todd Conley

 

[Lefty7mmstw]

I was a huge RL 17 fan. The velocitys were awsome. Gun shot great. Presures were fine. Then I show up at a May match with temps in 100s. Couldn't open my bolt and almost shot over a berm @ 750 yds. Took myself out of the match for safety. I will not shoot it ever again in my match rifle. I probably will in some of my hunting guns but not ever again in a match rifle. I am now shooting 4350 almost 100%.
My 2cents
Todd Conley

Some combo's will run 75 Kpsi without showing a hint of over pressure. I played with a strain guage on my last 7stw, and I was getting 58 Kpsi on one combo with rl25, but I went to 7828 and similar vel. and pressure signs were netting 70 Kpsi. A bit too much temp. would have gotten me a sticky bolt. You've got to either actually shoot in the highest temps expected or leave a bit of headroom for temperature.

 

[Thesteeleboy]

I was a huge RL 17 fan. The velocitys were awsome. Gun shot great. Presures were fine. Then I show up at a May match with temps in 100s. Couldn't open my bolt and almost shot over a berm @ 750 yds. Took myself out of the match for safety. I will not shoot it ever again in my match rifle. I probably will in some of my hunting guns but not ever again in a match rifle. I am now shooting 4350 almost 100%.
My 2cents
Todd Conley

Todd, can you tell me the fps difference in your RL-17 and H4350 loads. I know its an old post but I would sure like to know what kind of velocity changes I can expect. I shoot a 6mm WSM wildcat, 95gr Berger VLD with 56gr of RL-17, 30" Bartlein barrel @3650 on a 70 degree day and the same load shot 3620 @50 degree's and lost its accuracy. Totally unacceptable.

 

[toddconley]

I have never owned a 6 wsm but I would think 4350 would be way too fast. 4831 may be too fast. I guess I would start with 4831 ssc then go to h1000 and maybe retumbo. That is an extreme overbore cartridge with along barrel. I am assuming the slower the better.
T

 

[Edd]

On a 6mm WSM, I would start with Retumbo and if my case got full before I got good velocity, I would switch to H1000. I'd be surprised if you can use a full case of H1000.

 

[Clark]

This graph was produced for SH by Kombayotch.

Kombayotch, now a moderator of Canadian gunnutz, has replicated Hodgdon claims of temperature stability by taking a freezer and an oven to the range.
He heated and cooled the ammo and then measured the velocity of cold and hot ammo.

Me, myself:
I can work up to and get 3228 fps 130 gr 22" barrel 270 with long brass life by using Re17.
I would have bet big money that was not possible.
1) But the temperature variations in Re17 would require such a big safety margin that I would be back down to the performance of many other powders.
2) Further, the temp variations are not good for first shots at long range [hunting, not targets with spotters].

Right now I am a big fan of H4350, because of temp stability.

 

[elkaholic]

I have had very good velocity and accuracy with RL17 but have found it to be QUITE temp sensitive. The best two powders I've used are H1000 and Retumbo for being consistent........Rich

 

[barnesuser28]

H4350 in my 284 win changes .96 fps per degree of temp change.

 

[BigBboy25]

The cooler method doesn't take into account the changes in barrel stiffness or dimension when the temp. changes. I'm killing to 600 yards offhand with my 300 win; good enough for me.

First, if you're killing at 600 yards off-hand, try out for the Olympic team (and take a class in ethics and morals if game is included), especially if you're using a .300 win mag.

Second, what loads are you talking about with the 25WSSM? Factory loads? If so, factory loads commonly have 100fps extreme spreads.

Next, if hand loads, how tightly do you measure case volumes, powder charges, OAL's, neck tension, and what primers do you use. Also, what rifle is it out of? I've used the same ammo out of factory barrels and compared them to custom barrels and the extreme spread in custom barrels has always been much better than factory barrels.

Finaly, the 25 WSSM is very overbore; and I assume you have a 24" barrel, which means a lot of the powder is burning past the muzzle, this has proven to be detrimental in extreme spreads.

Finally, how close is your chronograph to the muzzle? You should place it 15-18' in front of your rifle in order to prevent false readings from the muzzle blast. If you believe that distance is overkill, I encourage you to repeat your tests at 18' from the muzzle, and see how your extreme spread compares. Even with you O35 chronograph.

My two degrees in engineering tell me you need to do a little more homework, you leave a lot to question and from what you say, I buy nothing of it. You seem to be an internet expert, and a very incredible source.

Cheers!

 

[Canadian Bushman]

H4350 in my 284 win changes .96 fps per degree of temp change.

Wow really, i had it at .6 in my app for my 308 win but im still in the early stages of proving it out.

On a side note, I think its important to state what cartridge you are using what powder in because ive heard rl-17 acts more stable as the operating pressure increases.