I loaded some 180gr speer in front of 59Gr 4831 SC. I then went to the range and chrongraphed this load. Two shots 2470&2490fps @ 10' from muzzel. This load was very accurate. The book says this should be about 2800FPS. I won't have a chance to chrono other loads with this rifle so Im askin if this looks right? The rifle is a Sako 75 23" barrel with magna porting (two horizontal cuts on the side and two almost on top). Is it maybe the porting or the load?

Seems slow, even out of a vandalized barrel. A similar load I tried a couple of weeks ago went about 2790 using Noslers out of a 24" normal barrel.

I would suggest checking the spacing of your chronograph screens. This is the easiest place that error can be introduced.

To check whether you have an "off" lot of powder, try it in some other rifles and compare your results with "book" indications. Two hundred fps variation between any two barrels is not unusual, but the 300 fps or more apparent in your '06 is.

This is out of a little hand held chrony, seems to be accurate with my other rifle that same day.

Iam getting 2690 avg with 60 grs of 4831 out of a ruger 77 22 in. 2400's seem a bit slow did you ckeck your crony with a known round.

I think you ARE getting only 2490 out of that barrel. 23" Magnaported barrel equals a 21" barrel at best.
With 4831, it just does not perform to book expectations.

Sorry

Maybe try some faster powders like 4895 or 4064.

Heider, if your chrony is one of the "fold-open" "Chrony" brand models, make sure it is all the way open and locked. Also, sun can play havoc with readings. I picked up a neat trick several years ago and it has eliminated the need for screens... put "frosted" scotch tape (not the totally "clear" kind") over each "eye"... eliminates false readings nearly 100%!

Brad

Another thing that may be the cause that I did not consider is the age of the powder. I got some of this from a friend who had a keg from back in the sixties, he said it was military powder from pulled 50 cal cases. Is it possible that it has lost power?

Correction, it is not 4831SC it is just regular 4831.

Terry I once had a 7mm mag with a Mag Ported barrel. Now before it was ported the velocity with a 140 grain bullet was 3160 feet per second. Now after it came back we checked the rifle with the same ammo, and the gun shot 3123fps. So I figured we lost 40 fps give of take a foot or two.

Heider, I don't think that the powder has "lost power". I simply think that it might be military surplus, which of course means that the burn rate can and does vary. FWIW - Dan

Are you using the same primer as the load you referenced?

The primer is a standard cci 200

How doses the pressure compare to factory ammo?? Check the pressure ring expansion and compare to factory. Be sure you are loading to full pressure. If you need to add more powder use a drop tube. You should be able to do better than that.

Okay! Military surplus 4831 is markedly slower than currently manufactured H4831 (which is in turn much slower than IMR 4831). In fact, original surplus 4831 is almost as slow as IMR 7828, usually being about 1 grain faster in my guns.

I have used scads of surplus 4831, which is now over 50 years old, and it is a truly great powder. I have never found any that was deteriorated.

With your '06 and a 180 grain bullet, pack as much of this powder in the case as you can (a drop tube helps tremedously). It actually performs best when moderately compacted. If you will use fired, neck-sized brass, you will likely pick up a couple of grains capacity.

Incidentally, surplus 4831 was not pull-down powder. And certainly not from .50 Browning. Bruce Hodgdon bought tons of it from the government in bulk and repackageded it. It was far too cheap to bother with as a "pull down". Besides, it was a powder manufactured originally for the 20mm cannon, not the .50 Browning.

For years I have used little else than surplus 4831 in most sporting cartridges from .243 Winchester to .338 magnum.

[This message has been edited by Stonecreek (edited 03-27-2002).]