H4831 in 6.5x55

C

crout

CGN Regular
Rating - 100%
152   0   0
Location
Rosemary, AB
I'm(soon) running 140gr amax moly in a 30" barrel. Hodgdon list max load at 47gr and a velocity of 2586fps. i'm assuming with a 24" barrel? I've seen load data with a 26" barrel and the velocity is about 2735fps can anyone tell me what the velocity would be like with a 30" barrel? If i'm using moly bullets should i moly the barrel as well to get my fps up?
 
crout, velocity will depend on several factors. Twist rate is one of the main factors. H4831 is also quite sensitive to temperature and primers used.
Most of the specs for the 6.5x55 that I've seen, are either from the 18 1/2 in model 94 carbine barrel or the 29 in Model 96 long rifle barrel. There should be a barrel length and twist rate listed at the description header on the manuals' page.
 
Yeah. i know i won't be able to find an exact velocity. i'm just looking for someone who runs a similar rig just for a reference point. or if someone can give me an idea of how many fps per inch of barrel you gain.

Hodgdons, to my knowledge doesn't list barrel length on their website but based on the load data given it is not 29" or 18.5"

how many rounds of moly coated bullets do i need to shoot before my bore becomes moly coated. i was under the assumption that you had to moly the bore seperatly to get a true moly coated bore?
 
I have never even seen a moly coated bullet, so know absolutely nothing about them.
However, one time when I was chronographing a 30-06, I wondered about making the bullet easier to go through the barrel. I chronographed five rounds of my 180 grain load. Then I took five more of the same batch, but before loading a cartridge, I lubricated the bullet that stuck out of the case, with STP engine oil additive.
When I measured the speed of the five with the lubricated bullets, they averaged about exactly 100 fps, SLOWER, than did the previous batch that had no lubrication.
Is this what the moly coated bullets do, also?
 
crout, is this in an M96 action, or a stronger "modern" action?

H4831, that's counter-intuitive, isn't it? Did you figure out why that was happening (FWIW the same thing happens with the first shot out of a clean barrel, and for the same reason too...)
 
I can figure out what is happening, wanted to prove it.
However, my point is whether the same thing is happening with moly coated bullets? If it is, then it would be the moly coated bullets that are counter productive.
 
The same thing happens with moly bullets - a lower velocity, for a given charge weight (the reason being that the shot start pressure is lower, because a better-lubricated bullet enters the rifling earlier).

With moly (or any other means of lubricating bullets) you are able to increase the powder charge, in order to get the original velocity. And, perhaps (this is where the "he-said/she-said" part starts) even go higher than that, to get higher than original velocity, without increased pressure.
 
It's a stevens 200 action 30" shilen barrel. lapua brass.
moly bullets are not my prefered choice but that's what was in my box when i opened them up. so i got 500 amax moly bullets to use up.
 
With the Stevens action you should be able to work up to and then past the max listed as it has to take in consideration the potential use in the older actions. Move up slowly by .2gr increments then back of when you see pressure signs.
 
I burned out a 6.6 x 55 Shilin 30" barrel on a Savage action.

Velocity was 2950 fps. Used 142 Sierra moly bullets.

4831 will leave a lot of empty case. It might be accurate. did not try it. I got best results with RL 22 and H1000.

Moly bullets need about a half grain more powder to get the pressure back up. makes the barrel easier to clean. Nothing to do with velocity.

If you ever make a batch of ammo that is too hot, just smear a light coat of greese ( your bolt locking lug grease) on the bullets. This will drop pressure about 5,000 psi.
 
Harold, most of my H4831 powder is of the old surplus type. I can guarantee it is temperature sensitive. I have chronographed some that is about 5 years old at different temps as well. The velocity differences between 25C and -30C are at least 200fps and definitely have different POIs. If we're talking intermediate, above freezing temps, there isn't much difference at all. That's the reason I switched to H414sl10, a bulk powder from Higginsons, slightler slower than W760.
 
Not that I doubt your testing but I've always read the H powders are renouned for temp insensitivity? I had some [Higginsons]Scott made clone H-4831 years ago that was a little slower than the real stuff but I guess it can vary lot to lot? we used it up on .270,300WM and 140gr 6.5x55 .A lot of deer and a couple moose later we burned up the 8 lbs......Guys loading for hot climates [Africa] have to back off a grain or two as well...........Harold
 
Ganderite said:
4831 will leave a lot of empty case. It might be accurate. did not try it. I got best results with RL 22 and H1000.
Click to expand...

I'll give those powders a try if the h4381 doesn't work. It's really old powder but looks and smells new. I've started really low and have worked up to 47.7gr. the throat on my barrel is not very long so at 47.7gr the load is compressed. i've read form others who put 52gr in the case? must be the new H4831
 
You must log in or register to reply here.
Back
Top Bottom