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View Full Version : IMR 4895 and WC860 in 30-30



JohnH
09-16-2006, 11:15 PM
While I've mostly used Jeff Bartletts #107 for reduced loads in rifle cases, I recently decided to see what I could get out of my Savage 340 30-30 using some different powders.

1st I tried out was WC860. My first loads were with 35 grains, and as one might suspect left a lot of unburned powder in the bore. As I've duplexed this powder in past, I decided to duplex it in the 30-30, using 2 grains of IMR 4895 (milsurp from GI Brass as well). Not only did the duplexing clean up the unburned 860, 20 rounds using the Lee 312-185 shot a very nice 1 1/2" group. Average velocity is 1520 fps.

But I dislike duplexing because I'm lazy. It is a PITA to hand throw 2 grain charges of one powder before throwing charges of another on top of that. One more list of too many things to keep up with. Not that it's complicated, just I'm forgetful, and I like the KISS principle....Keep It Simple, Stupid.

So I set off to find another load. 7383 is not a reduced velocity 30-30 powder. Ask me how I know ;) . By the time the pressure is up to where the powder burns decently, we are well past reduced velocity. So I took down the 4895 and began to play with it.

According to my NRA Handloading book, 4895 can be reduced to 60% of case capacity without erratic burning, so I started out with 20 grains and got some very decent grooups, but the 1st shot was always about 100-120 fps faster than the four that would follow it. Average velocity is 1293, but it was not unusual to see the first shot clock as fast as 1460, 1360 was common. (I fired over 100 rounds playing with this today)

My first instinct was to raise the powder charge, but on reaching 25 grains, which is just above starting loads with this powder in Lymans manual, I was still seeing 100+ fps variations, but now not only at the first shot, but throughout the 5 shot strings as well. Hmmmmmm.......

I dropped back to 20 grains and switched from standard rifle primers to magnum primers. My thought was to increase the flame for better ignition. I got the same results as 25 grains of powder gave me, wide velocity swings across the shot string. Hmmmmmmm.......

I began to wonder if what was occuring was that the force of the heavier charge/primer was blowing the bullet into the bore before the powder had begun good ignition. Would a crimp help? 10 rounds well crimped said no. I then switched to a Large Pistol Magum Primer (CCI 350)

Velocity swings dropped to a max of 60 fps across the shot string, the high velocity of the first shot disappeared, and I was rewarded with nice 1 1/2" groups again.

I've no good explaination for the high velocity of the first shot. But I do think that the variations of velocity I was seeing across the strings was a result of the expansion of the relative volume of the chamber, caused by premature entry of the bullet into the bore. The result was a reduction of pressure which adversly affected the peak pressure of the load , but perhaps as importantly where in time in relation to the bullet position/location in the bore that peak occured. I know that's poorly worded.

44man has spoken to the importance of a good grimp to insure good ignition. In my case the crimp or lack of made little difference. Perhaps I simply couldn't apply enough crimp to create a positive effect without first buckling the shoulder. But without doubt good ignition and consistant pressure rise are essential to good accuracy.

If I'm right, perhpoas I can improve how a 30 grain charge of 4895 in my 375 JDJ shoots.........

Bass Ackward
09-17-2006, 12:51 AM
Hmmmmm. Sounds logical.

But that is crazy using pistol primers in rifle cases. :grin:

Personally, I'd go back to the 7383 myself.

drinks
09-17-2006, 10:36 AM
A Lee collet type factory crimp die will put a uniform crimp and will not crush any brass, I use one for everything, even modifying , usually by making a spacer, so I can crimp cartridges Lee does not made dies for.

krag35
09-17-2006, 09:12 PM
I have a Savage 340, and it does it's best with standard Lg Pistol primers. I use 21 gr of 4895.
krag35