I have a 30-06 with an 18.5 inch barrel. I shoot 180gr ballistic tips. The question is, what is the most efficient and consistent powder to use with this combo? I presently use I.M.R.4350 with pretty good results. I think that there must be a lot of unburned powder because of the horrible muzzle blast. It wouldn't bother me to leave it alone, but I do want to use the rig to it's max ability and efficiency for that barrel length. Any help out there? Thanks

I have no experience loading for a 30-06 with a barrel that short, but I ran some QuickLoad models.

Your IMR4350 is running about 95% burnt, so the muzzle blast is very believable. QL says that Accurate Arms XMR4350 will give you about the same velocity with 99.9% burnt. It will be a 5% compressed load, so you'd likely need a drop tube.

IMR4895 is also 99.9% burnt, but will drop your velocity about 60 fps, and the case will be about 96% full. This is a very traditional, low-risk answer to your situation.

I would try the XMR4350. See http://www.accuratearms.com/rdata4.html#anchor649799

The ballistic tip holds together fairly well at 2700 fps, but I would still not advise it for elk, except in broadside shots. It is devastating on deer and pigs.

Good luck,
Don

Maybe, IMR 4895. If I am thinking right on that, a buddy chopped a PSS in 308 and the muzzle blast was considerable. With a short barrel like that you will obviously get more muzzle blast, but I think his fix was 4895. Though the muzzle blast always stayed relatively high.

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I am currently using 57gr of IMR 4350. Was the loading you referenced the 57gr load of the accurate 4350? as far as burn rates go is the 4895 quicker or just more efficient in the shorter barrel. The oal for my current round is 3.400 inches. Would that still be 5% compressed and mandate the use of a drop tube? I have used the 180 BT for years and it works wonderfully on white tail. I have never had access to a chronograph so I don't know the speed but the round is extremely accurate for a hunting rifle. The noise from the muzzle blast has never been an issue for me, it's just that a guy at the Ben Avery range made the comment that I could probably use the rifle as a sandblaster with all of the unburned powder. That is what led me to the first post and got me thinking about the efficiency aspect. Thanks for the info.

Yes, The recommended load of XMR4350 was 57 grains. If you up the length to 3.4" then the max charge goes up to 57.5 grains and it's still 5% compressed. You should be running about 2650 fps at that load. Five percent is at the edge of needing a drop tube. Try it without and see if there's too much crunch.

Do not be fooled into thinking that XMR4350 is the same as IMR4350 (or the same as H4350.) The XMR4350 is quite a bit faster as evidenced by the 99.9% burnt for it rather than 95% burnt for the IMR4350.

The burn rate for IMR4895 is roughly the same as the burn rate as the XMR4350, as evidenced that it is also 99.9% burnt. It has less energy for a given max pressure than the XMR4350, that's why it yields a lower velocity.

I would use the XMR4350 and a WLR primer. I suspect it would solve your "sandblaster" problem, while keeping the max velocity. As far as accuracy goes, if you change anything at all it's a crap shoot. I have had very good luck with the Accurate Arms powders, but I don't know that I'd change a working recipe on a chance comment at the range.

Don

[This message has been edited by Don G (edited 04-18-2001).]

Don, what is the quick load thing you were talking about? It sounds pretty interesting in that it would give theoretical burn efficiency for a powder and barrel length. It sounds like a pretty useful tool.

It is a computer program that models internal and external ballistics for known powders and bullets. The powder definition file is not complete, but has most of what I'm interested in.

It gives pressure and velocity curves, muzzle velocity and pressures, etc.

I got it from http://www.neconos.com for about $150.

I have not tried any of the other computer programs. I like this one ebough to keep it updated.

Don

Don,
I also have quickload and played with IMR 4198. That was the only combination that I could get to around 2475 fps with a muzzle pressure of less than 10,000 psi (actually 9435 psi).

DaveC,

What was that in?

Don

Don -
In a response to Carnivore's post on powder efficiency, you said:
'The burn rate for IMR4895 is roughly the same as the burn rate as the XMR4350, as evidenced that it is also 99.9% burnt'.
Are you saying that X4350 and I4895 can be loaded to the same levels (57 grains I4895/180 Grain in 30-06), or, did I misunderstand?
R-WEST

No, The powders are not at all equivalent in the sense you are using. If you do what you said you would ruin a rifle (or worse). Quickload says the max pressure for 57 grains of IMR4895 is about 90,000 PSI in the 30-06 w/180 gr. BalTip. That is hotter than a proof load.

It just so happens that when the powder load is varied to generate the same max pressure (the condition specified for that computer run was 55000 PSI) with that bullet (180 gr NosBalTip) in that case (30-06) the 57 grains of XMR4350 and 49 grains of IMR4895 both hit 99.9% burnt at the end of that 18.5 inch barrel. That's what I meant by "the same burn rate". My slow-typing-induced shorthand is catching up with me again.

The actual burn rate is a very strong function of the instantaneous pressure.

Note that all this is very much a conjecture. Quickload results should always be used simply to choose the powder to buy, then the load worked up according to standard practice and published data.

H. Broemel is, I'm sure, very thorough in the best German tradition, but I would never trust my life to the results of his program (or anyone elses) without a reality check.

I don't like to give specific powder charges off of Quickload for this reason. You may note that I did not mention 57 grains of anything until prompted specifically by Carnivore.

Don

Don -
Got it!! I misunderstood.
R-WEST

Don G __

Good advice. "QuickLOAD" is a "Predictor". Any data forthcoming is an estimation based mostly on assumptions and related mathematics. But then, so are most of our other ballistics software programs. Herr Broemel himself stipulates that "burning rate" [as we use it] is a misnomer.

The "cut and try" method of selecting a gunpowder for a particular application is still the only way to go with sfaety.

Good shooting.

Robert