Author Topic: Handloading the 30-06 for carbine-length barrels (Read 948 times)

EdK · « **on:** October 11, 2005, 06:26:35 AM »

I'm interested in determining what would be the best powder to use in the 30-06 cartridge for 150-180gr bullets and shorter barrels (e.g. 18.5" or 20") I'm aware the best powders for maximum velocity in a longer barrel are also typically deliver the best velocity in the shorter barrels. In this case "best" could be interpreted a little differently:

It's generally agreed that this round under 250 yds is way more than is needed for whitetail, so why put up with the inevitable blast that will result while trying to wring every last fps out of the gun?

I'm guessing that a powder on the fast end of the spectrum is called for. Anyone have any pet loads for such an application? I'm sure this drill is a "been there, done that" for someone here on the forum but using the search I could not find anything on the subject. Thanks in advance for any help.

PA-Joe · « **Reply #1 on:** October 11, 2005, 06:55:58 AM »

IMR 4064

PaulS · « **Reply #2 on:** October 11, 2005, 07:24:55 PM »

Keep in mind that pressure is what gives the blast and you get that pressure in all but reduced velocity loads or loads with very slow burning powders. (too slow for the cartridge/bullet) Reduced velocity loads don't provide enough velocity in any barrel length for good hunting so you are left with blast from the "normal" powders or flash from the slowest burning powders.
Having stated the obvious I think that I would look at the lightest hunting bullets (130 grain 30/30 type) and load normal (on the fast side) powders (IMR 4895) and work it to get the maximum accuracy in your rifle. This will involve keeping the distances reasonable (probably inside 150 yards) and watching your shots.
PaulS

EdK · « **Reply #3 on:** October 12, 2005, 01:42:05 AM »

Even though a 24" barrel is what most might like to have in their hands when touching off a 30-06 round, the fact of the matter is that 22" is now somewhat standard. Having said that as soon as someone posts about shortening their rifle to 20", the posts generally run along the lines of: "Don't do it! you'll gain little in portablity and be saddled with that awful blast" By the way the replies come in you'd think it more of a flamethrower/noisemaker than in a 15" Encore handgun. :eek:

Well, I'm looking to load for my Ruger #1 International which is 20" to start with - I didn't cut anything down :lol: While this particular rifle may not be all that popular I know that 18.5 Remington carbines are and so on. Hence I figured this has already been worked out long ago.

Once again "best" in this context means:

PaulS · « **Reply #4 on:** October 12, 2005, 08:16:21 PM »

EdK,

The powder in a small arms cartridge burns completely in the first few inches of the barrel. The flash is caused by super heated gasses and carbon that is exiting from the barrel not powder that is unburned. The shorter the barrel is allows more of this to exit while it is still hot enough to be seen. Powders are selected by the available powder space, the weight of the bullet used and the SAAMI pressures accepted. That is why the same powders that produce the highest velocity in a 26 inch barrel produce the highest velocities in a shorter length barrel.
No matter which powder you use, if you use near maximum pressure you will have the same blast from the release of that pressure as the bullet exits. Faster burning powders will slightly less pressure on exit due to their faster pressure curves but because of that faster curve they give lower velocities because they do not push the bullet with high pressure for as long as the slow burning powders. (the average push is less for fast powders than it is for slow powders) Also peak pressures must remain at or below the SAAMI standard.

PaulS

EdK · « **Reply #5 on:** October 13, 2005, 02:40:01 AM »

PaulS

Thanks for straightening me out a bit on the internal ballistics theory. I don't think I was too far off but after your last post I have a clearer picture of what is going on inside the tube.

So in summary I should be able to load using a powder which is on the fast side of normal (such as PA-Joe's recommendation of IMR 4064) to do what I'm after. Understanding that I'll sacrifice 100fps or so because of a steeper pressure curve which will not push on the bullet as long/hard. While the residual pressure level venting at the end of a 20" tube might be more like that of a 22" tube loaded more "normally", I should always expect at least some increased blast/flash over a longer tube.

Again, I wasn't looking for a significantly reduced load - just trying to equalize a bit for the loss of 2".

PaulS · « **Reply #6 on:** October 13, 2005, 01:44:30 PM »

EdK,
the reality of your situation comes down to this:

IMR 4064 will reduce your velocity by 150 fps over the use of W760 with maximum loads of both. Reducing the load by 2 grains will reduce the velocity by another 100 fps. By using the faster powder with the same bullet in the same barrel (reference: Speer #13) They use a 22 inch Remington 700 in their tests and in my experience are very close in their velocity reports to my 24" Remington. The maximum W760 load gives just over 2800 fps from the 22 inch barrel (yours might be as much as 50 - 100 fps slower) the maximum load of 4064 gives 2640 fps (again your could be slower) a reduction of 1 grain gives you about 2600 (or slightly less).
In my opinion - just an opinion - you would get the ballistics you want only with the W760 or IMR4350 loads ( the best powders for the cartridge / bullet combination) but you would have to put up with the noise and or flash that each gives. Try it and see what it is like - it may not be that bad.

PaulS