5744 Hot?

[JohnH]

I'm shooting 18 grains of 5744 under the RCBS 257120 in a 25-06 Encore. The velocity average is 1670 and the load is pleasingly accurate, regularly delivering 1 1/4" groups at 75 yards. But it gets the barrel hot in a hurry. 5 rounds will get the barrel hot enough that while I can touch it, I don't want to shoot more through it till it cools. As I shoot in my back yard and only load 5 cases at a time, it is not so big a deal, but I do plan on taking this load to a prarie dog shoot for short range plinking. Anyone else shooting 5744 in anything notice it heating up the barrel quickly?

[gasboffer]

I've used it in several calibers, always shot well, pretty accurate in everything.
I just couldn't stand to look at all those crumbs that it left in the bore.

[felix]

The newer lots 5744 have circa 20 percent nitroglycerin. In your situation, you want the early issue (dust all over the can/bottle), when you can find some for that exact burn speed. You will be best served with a single base powder, say 4227, N120. ... felix

[Bass Ackward]

John,

How hard are your bullets?

Harder bullets in this case will have less obturation, thus less friction and thus generate less heat. And .... I always water drop my plinkin stuff and use a magnum rifle primer so that it burns in the case. Get more shots per string that way.

[drinks]

Bass;
Your experience is the opposite of mine, when shooting PB .45-70s, the A/C wws show lower velocities than waterdropped wws, same bullet, same powder and charge weight and same rifle.
I thought the higher velocities were from more resistance/ back pressure from pushing the harder bullet into the rifling and down the barrel, using the powder more efficiently.
Do you have pressure measuring equipment, I do not, still on my wish list.

[JohnH]

drinks, look at it this way..... if it takes 10,000 psi to obturate a bullet, but one is only making 8000 psi, the bullet will not obturate against the bore, creating less friction, creating more velocity. Friction equals drag which will translate into velocity loss, which explains a softer bullet moving at a slower velocity, because a softer bullet requires less pressure to obturate against the bore.

Bass, I'm currently using 50/50 WW-Lino. Runs about 18 BHN without all the water dropping mess. I've a couple hundred pounds of lino and have decided it is doing me no good to hang onto. Shoot and enjoy, besides, it was free :)

Felix, I was afraid that was the case. Time and money being what it is, experimentation with different powders will have to wait till after the shoot. I'll just have to be conscious of how rapidly I'm shooting the load.

[Bass Ackward]

Bass;
Your experience is the opposite of mine, when shooting PB .45-70s, the A/C wws show lower velocities than waterdropped wws, same bullet, same powder and charge weight and same rifle.
I thought the higher velocities were from more resistance/ back pressure from pushing the harder bullet into the rifling and down the barrel, using the powder more efficiently.
Do you have pressure measuring equipment, I do not, still on my wish list.


Drinks,

Opposite? Are you kidding? Look at my handle?

You can very well be right under your conditions. I didn't consider velocity here at all, just how to reduce barrel temperature from 5744 with a light or plinker load. I know John used to be a soft bullet fan.

If your asking about my pressure experience, I can tell you this way. I once had a hotter load in 30-06 using a 35 BHN bullet that was perfectly safe measuring case head expansion. Idiot me decided to try ACWW with the same load for hunting and stuck the bolt. The case was expanded into the extractor slot.

So I would say the softer lead definitely threw more pressure. :grin: I owed it to increased friction from obturation. I .... didn't .... measure the velocity. :grin: