Author Topic: Using Slow Burning Powders In Semi-Autos (Read 883 times)

firstshot · « **on:** July 19, 2004, 04:49:59 PM »

I just recently got a BAR 30-06 and I have read so much about "slow burning" powders being bad for use in semi-auto's, with the general consensus being.......use "medium" burn rate powders only!

I was planning to load some Sierra 180Grn Game Kings and someone had recommended trying IMR-4831, which definitely is NOT in the "Medium" burn rate category. In fact, it's a little slower than IMR-4350 & H-4350. I've shot a lot of IMR-4350 in my gun, BUT, just to be on the safe side, I thought I'd better do some checking first.

I talked with Sierra's Ballistic Services department, Browning and Owen Winchester Ammunition and questioned them all about slow burning powders & the BAR. As you can imagine with today "legal" atmosphere, getting a straight forward "yes / No" answer....well, it just didn't happen.

Sierra's Ballistic Services department (1-800-223-8799)
I told them I was going to be loading the 180grn Game King and wanted to know if using the slower IMR-4831 could potentially damage my BAR. In short, I was told "the Browning BAR can handle any powders listed in the various load manuals as long as you stay within the recommended Min / Max loads. The Browning BAR is designed to take it!"

Browning - (1-800-333-3288)
I spoke to a Joe at Browning's Customer Service dept and he more or less stuck to what was said in the owners manual, but phrazed it in the positive instead of the negative (see above note). He said "you can use any powders listed in the published load manuals without damaging your BAR as long as you stay within SAMMI specifications". He said "get a chronograph and stay within the published min/max loads and at or below the published velocities". He also said (just like the manual) that "you shouldn't develop loads that generate more pressure than that generated by commercially available ammo that was loaded within SAMMI specifications".

Owen Wincheste Ammunition - 1-800-356-2666
The first time I called Browning, the guy they said I needed to talk to wasn't there and they gave me the number of Winchester (both part of the same company) and that someone there could probably help.

I called Winchester and asked for someone that could answer a reloading question. I talked to Brady, specifically asking about the BAR port pressure vs slow burning powders like IMR-4350 and IMR-4831. I also told him what Browning had said about commercially available ammo being OK for the BAR. He said he "wasn't really that familiar with BAR's, but based on what Browning had said, he couldn't imagine it being a problem at all as their Winchester 30-06 180grn ammo is loaded with winchester 760 powder which was basically the same as H-414, H-4350, IMR-4350".

I checked the winchester website and found that their 180grn 30-06 ammo is loaded to the following velocities:
Accubond...............2750
FailSafe...............2700
Ballistic Silvertip....2750
Power-Point Plus.......2770
Partition Gold.........2750
Power Point............2700
Silvertip..............2700

So what does all of this mean? Well, Browning says it's OK to shoot, in a BAR, commercially available ammo or hand loads that approximate commercially available ammo & do not exceed SAAMI specs. To me that means that since Winchester is loading their "commercially available" 180Grn 30-06 ammo to 2700-2770fps using a powder equivalent to IMR-4350, then it's OK to shoot the Winchester ammo or similar handloads in my BAR.

I have since loaded and shot "work up loads" of Sierra 180Grn Game Kings on top of IMR-4831 with nothing less than excellent results and no cycling issues. If anyone is interested, I'll post the results but this post is already way to long winded. Just wanted to lay some ground work for what I hope will be a good discussion.

Anyone else have actual experience using the "slower burn rate" powders in their Semi-Auto's?

firstshot

hogship · « **Reply #1 on:** July 19, 2004, 05:17:23 PM »

Howdy Firstshot......

The information you got sounds reasonable to me.

I'm aware of warnings against using slow powders for use in the M1 Garand.....and not sure if the thinking applies to your BAR.....never had a BAR. Does it use a gas piston for cycling the action?

I am getting excellent results with 4064 in my Garand.....and it's in the "medium" burn range.

Is there a particular reason why you would prefer a slower powder?....or is the 4831 a powder you happen to have on hand?

Good to talk to you once again.

hog

firstshot · « **Reply #2 on:** July 19, 2004, 05:54:53 PM »

hogship

I had been working up loads for the Nosler Ballistic Tips, both 180 & 165 grns & IMR-4350. Actually the 180 BT shot pretty good with avg 1.4" groups @100, but the 165G BT's were grouping at 2-4".

The only reason for trying the IMR-4831 is that someone had recommended Sierra Game Kings on top of 4831 as a very accurate hunting load. Turns out, my gun REALLY likes that combo. Out of 12 "work up" loads (in 1/2 grn increments), 7 three shot groups were sub MOA, 3 groups had one flyer (my fault - not the gun) and the other two groups were the first two "low powder charge" groups. Overall average group size for 12 groups (flyers & all) was 1.09" CTC @ 100.

Both these powders are on the "slower" end of the scale and although I'm somewhat reluctant to walk away from these good results, there are so many powders out there it doesn't make sense continuing to use them if there is a chance of damaging my gun.

I think a lot of the "don't use slow burning powders in semi-autos" does relate to military guns like the garand, where port pressure can be an issue, and that over time that caution has come to apply to all semi-auto's.

Would just like to get to the bottom of the issue one way or the other.

firstshot
---------------------------
Make your first shot count!

Rick Teal · « **Reply #3 on:** July 20, 2004, 11:58:12 AM »

The burn rate concerns with autos relates to the gas port settings in the particular rifle. Most of my experience is with Remington 742's, and in that rifle, I can say without hesitation that the rifle will not function properly with slow powders. In mine, I settled on a load using IMR4320 for deer, but I know others who found their rifles preferred IMR4064 or IMR4895.

I've recently picked up a Browning in .308, but haven't had a lot of chance to experiment with powders so far. Browning's gas control system may be set-up to handle a wider range of burn rates than the Remington, but you can only discover this through experimentation, as far as I know.

I've never concerned myself with MOA accuracy, opting more for terminal performance and reliability.

It seems that so far your load is working OK. I'd graph the loads to see if it's giving me the velocity I need to get optimal performance out of my bullets, and check the brass to see if there are any unusual things happening to it such as marked or bent rims. Id check to see if I'm getting an unusual amount of carboning up of my chamber (either of which could indicate that the bolt is releasing too early). This might indicate the powder is too slow for the gas system set-up.

firstshot · « **Reply #4 on:** July 20, 2004, 06:08:24 PM »

Rick

The gun seems to be functioning properly in all ways. No unusual amount of carboning up of my chamber and no issues with the brass such as marked or bent rims. No pressure signs on the brass. The gun cycles well and ejects the brass with no problems. No problems chambering the first round or chambering a new round after a shot.

I don't have a Chrony but a frind of mine does and he has agreed to go out with me and check the velocity of the loads.

Have you had a chance to shoot your new BAR .308 yet. I was really surprised at the mild recoil of the BAR 30-06. I've been shooting a 6.5x55 for the past several years and really expecting the 30-06 to give me a bit more of a thumping. The felt recoil is a little more than the 6.5x55 but not much. I would imagine that your .308 is going to be sweet to shoot as well.

I was also surprised at how accurate the BAR's are, especially after reading so much about how much more accurate the bolts are supposed to be compared to the Auto's. Any time I can shoot MOA or sub MOA, I'm good to go.

Working up some Sierra Game King on top of IMR-4350 now. I strongly suspect that changing the bullet from Nosler BT's to the Game kings had a lot more to do with the accuracy improvement than switching to the IMR-4831. I had been loading the BT's with IMR-4350 (No cycling probs with the 4350 either)

Seems like the 4350 powders are the most recommended powders for the 30-06.

Let me know how that .308 shoots.

firstshot
-------------------------
Make your first shot count!

Rick Teal · « **Reply #5 on:** July 21, 2004, 10:55:43 AM »

firstshot:

I haven't shot it yet, but I'm hoping to get to the range tomorrow. At first I'll just shoot 147 grain milsurp, but I plan to hunt with 180 grainers, so I'll probably try a couple of shots with some loads I made for my bolt gun.

I'll let you know how things go.

It sounds like you have a good load, as long as you're within your velocity perameters.

Rick