Powder for 9mm carbine loads

[briandg]

My personal thoughts would be hs6. It is almost certainly the densest, slowest burning powder that can be used in a nine, producing higher velocities than most other powders, and it will be very efficient in your load. You should not go above any +p loads. Your system isn't gas operated and isn't any stronger than a typical heavy handgun, imo.

[random guy]

random guy: "Alternatively, gun makers could engineer the carbine to function with SAAMI spec ammo including +P, and handloads at least to standard pressure specs."

I suspect they do that now.

Makes sense but reportedly owners are blowing out caseheads somehow, in some carbines.

Maybe we can get some specifics on these events.

[briandg]

If the thing is a blowback, that's not a reason for the case failures, just to be clear. Many firearms operate as blowback designs that carry full power loads.

A blowback system requires a few things. First, it has to have a heavy weight breech block that holds its place against the pressure for a brief moment, holding in place until the pressure spike is over. It has to have a heavy spring, to add further resistance. The spring must also work to absorb all of that rearward movement possible, so that the bolt doesn't hammer against the receiver.

Blowback systems that don't work on occasional guns are going to generally be because of ammo or spring, if all other things are equal. Using ammo with slow burning powder or some similar issue can delay the pressure spike until the bolt is already moving. A bolt without enough mass or a spring thAt is sloppy can cause the bolt to slide backward during the pressure spike.

If a blowback system has a reasonably well supported chamber and it routinely blows out case heads, the probable, and almost certain answer is that the bolt is retracting early, while the pressure in he case is still high enough to tear the brass.

[jetinteriorguy]

I have been using 5.9 gr of HS-6 with a 124gr HiTec coated bullet for over a year with good results in both my pistols and the carbine. I've also used the same charge with Extreme copper coated as well. I've shot well over 500 rounds of each of these loads with no problems. I'm going to have som time off coming up and will report back how well the PowerPistol works.

[briandg]

Power pistol should work well, I've used it before, but switched to another. I've still got five pounds. Loading a few grains at a time takes a very long time to empty a can.

[highrolls]

random guy: "Maybe we can get some specifics on these events."

That would be very useful if you find some.

briandg: "Many firearms operate as blowback designs that carry full power loads."

This. All of the carbines I used for load development testing are +P rated.

briandg:"The spring must also work to absorb all of that rearward movement possible, so that the bolt doesn't hammer against the receiver."

The carbines I use for testing have a recoil buffer to prevent this. As a side note, what happens during recoil can be modeled with cycle rate calculations. Just because it is a semi-auto does not mean cycle rate does not apply. The primary determining factor for cycle rate is counter intuitive a bit. Making changes to the spring constants do not have as much of an effect as you would think. Making small changes to the bolt mass is where the drastic changes occur. Let me example what I am trying to communicate.

briandg: "If a blowback system has a reasonably well supported chamber and it routinely blows out case heads, the probable, and almost certain answer is that the bolt is retracting early, while the pressure in the case is still high enough to tear the brass."

I am inclined to agree as long as the case is not seeing overpressure, like unto a triple charge of bullseye. Re-stating for a standard pressure, I think your description is good but I would be inclined to correct that problem by increasing the bolt weight until the case bulge goes away. No ammo or spring change necessary.

jetinteriorguy: "One thing I do, I use a brass catcher so I can easily inspect all my brass for pressure signs as I work up any loads."

Danger will robinson ! You are exhibiting the early signs of becoming as anal as I have about load testing. Pressure signs in pistol calibers requires a tea leaf reading talent. I create and label and organize such testing in multiples. I generally test 3 to 5 firearms at a time, same caliber test loads, laid out vertically, and study them under a good, bright lamp. That's when they begin to talk to you like a rifle case can. You also need a reliable bench mark load fired in each weapon as well. Example, row one shows one case with a bright extractor mark. Row two adds two more with bright extractor marks.... to firing pin crater mark changes, pin- hole primer edge leaks(magnifying glass),and so on.

[briandg]

I once had a very normal load blow out at the case base. A middle range load of accurate two. The brass was bad, the metal was crystallized. The thing tore out and peeled counterclockwise, leaving a fingernail sized shred of brass hanging off.

The thing fit the chamber exactly. It honestly popped open down inside the actual heavy web, and tore upward.

It was the most freakish event I've ever seen.

[random guy]

Does a blowback 9mm tend to stretch brass more than a locked breech? If so, this could be an issue with repeated firings of the same brass or even on the first firing.

Aside from the variable of brass composition and condition, the main factors in safety would seem to be pressure to time after ignition and bolt movement to time after ignition. It would be great to see these functions plotted for any gun and load in question, looking for consistent and minimal exposure of unsupported brass to high pressure.

Obviously blowback can work even under considerable pressure but it lacks some of the regulating devices of locked breech designs and is more delicately balanced.

[jetinteriorguy]

Thanks all. Good stuff, definitely things to consider. I always stay well within manufacturers published loads and only load for accuracy, not for the highest velocity. I have found over 30 some years of handloading the most accurate load are usually found in the middle range of published data. Probably the best thing I've gleaned from this is not to think of the carbine so much as a rifle, but more of an enhanced pistol. Just a means of extending a pistol rounds usability out to a longer range, in my mind basically about a 50 yd limit is good. I'm heading to the range tomorrow with my PowerPistol loads and will report the results.

[highrolls]

for briandg, I trust that neither the shooter nor the gun was adversly impacted by that blow out ?

random guy: "Does a blowback 9mm tend to stretch brass more than a locked breech?"

My experience has been that both action types actually shorten the brass. Resizing the brass streaches it out a slight bit. My longest experiment in the area was 17 reloads of selected brass. Over that experiment, the long term effect of the fire-shorten, resize-streach, was that over the 17 reloads, there was a cumulative shortening, meaning the test cases ended up slightly shorter than when they were new. I had discarded around 50 percent for various reasons by the time reload 17 was fired. While I could have carefully prepared the remainder for another reload, the work necessary to do so was becoming exponential. Case rim dings had become gross, the case head-stamps had become unreadable, and the prior reload (#16) had resulted in a significant number of case discards due to neck splits. While I had expected to wear out the primer holes, I do not recall discarding a case due to that. Early discards after just a few reloads were due to insufficient case-neck tension, and were from the same brand. These types of efforts are fun but you need to take good notes and a few photos cause memory just won't do it.

For jetinteriorguy, my experience with 9mm carbines leads me to recommend that you avoid lead and even plated bullets if you shoot a lot. FMJ only unless you like spending more time cleaning and less time shooting. Also I would say that 100 yds is really pushing the 9mm in a carbine. Also if you like power pistol, don't neglect the silhouette loads. They are opposites. Power pistol is the flashy, silhouette does not flash (well it does in the IR range but not visible.)

[random guy]

Over that experiment, the long term effect of the fire-shorten, resize-streach, was that over the 17 reloads, there was a cumulative shortening, meaning the test cases ended up slightly shorter than when they were new.

Got to admit, I didn't see that coming. I'd call that very good case life. Your 124 gr loads in particular are plenty healthy and use powders which are toward the slow end of optimum (best for performance). The fact that you had no case head separations or blowouts says a lot. Your blowback systems are obviously working quite well.

Brass is moving around to some degree but probably not the way I imagined. It would be interesting to section a case after such an endurance test as yours and compare to new. Might be nothing noticeable at all though.

The few carbine blowups I've found are often with factory ammo which varies in quality and ballistics. The blowups are probably most likely a product of poor firearm design and/or marginal ammo. Guns will have varying degrees of chamber support, chamber pressures vary greatly as does brass itself. Bolt and spring weight will surely vary.

My original thought on this subject was to take the Mythbusters ultimate approach of making the failure happen (theoretically at least). What factor would most easily do this? I'd guess that powder burn rate would be well down this list, at least among those powders which are appropriate to the cartridge to begin with.

[briandg]

High rolls, there was no injury, no damage. I looked at that thing and thought about it for days, sectioned cases, used a microscope, even, and can't understand why it happened like it did.

I wound up with soot all over my hand, and my hand tingled for hours. When you look at case blowout photos, nothing even remotely looks like mine. The drip started at the very heaviest part of the case and peeled upwards to fold over the exposed chamber ramp.

I sometimes wonder if that case head would have separated in a more fully supported chamber.

[briandg]

The shortening brass always sounds ridiculous, but it's pretty well documented to be correct by various "researchers".

With any weapon that rests on the case mouth, pressure will push it back to the breech booth before the case walls can stick to the chamber walls. Any stretch from friction would be minimal. It would require a very rough chamber to draw the brass out.

This comment doesn't apply to bottle necked shoulder seating cartridges, the interior ballistics aren't even remotely similar.

In the reloading process, we resize, and that compresses the brass and will literally reform it on the molecular level, over many cycles, it will have forced the entire brass tube inwards and downwards, and with resizing, it probably does some really strange stuff as the expanding gasses try to push the inner surface forward, expands the tube outwards, and then the outer surface is crushed inward and downward.,

[ShootistPRS]

When the round is fired the case expands outwards against the chamber. This stretches the brass diametrically. When you size the brass the length is not constrained so the stretched brass is squeezed toward the case mouth which is the easiest flow path for the brass.

In the last 45 years of reloading I have never had cases shorten regardless of their shape. I run all my cases through the trimmer with each reload and there are always some that trim, even if it is just a scrape on the case mouth.

[jetinteriorguy]

Finally got to the range with my PP loads. Whoa, even at the lowest level of 5gr I had primer flow, tried 5.2 and saw a substantial increase so I shut it down. Now I'm not 100% sure it's due to over pressure since this is the first time I've ever use S&B small pistol primers and wasn't sure if maybe they tend to run on the soft side, but the recoil seemed substantial enough to just shut it down. At least accuracy was good at 5gr. I think I'll try the same range from 5.00 to 5.9 with CCI small pistol primers and see what happens. I'm also going to reduce my start load by .5 gr and try the S&B primers up to the 5gr mark, and will start the CCI primers at the 4.5gr mark as well. I did shoot several of my standard 5.9gr loads of HS-6 with very good results. As for shooting HiTec or Copper coated bullets, I've put thousands of them through all my pistols and the carbine with no noticeable ill effects. I do clean my guns every few hundred rounds, but that's just something you should do anyway IMHO. I don't believe in cleaning them after every shooting session but don't like to neglect them either. Guess I just believe in taking proper care of my equipment.

[rock185]

Jet, surprised your PP load was showing pressure signs. Within my humble experience, PP is a bit slower,about 10%, than Unique. I've loaded thousands of rounds of of 115,124, etc. 9MM with 6 grains of Unique without issue. Wouldn't think PP would be an issue at all with the loads you tried. I have used most major manufactuer's primers but never S&B, so wonder if they are bit soft or have thin cups,etc? I've found the CCI #500 SP primer to be a very good one for high pressure loads in 9MM, 38 Super,etc. The CCI #200 resists pressure almost as well. FWIW, my carbines have been the Marlin Camp 9s, 3 of them. These are very lightly sprung with 11# recoil springs from the factory. Until recently, I always used the Wolff 21# recoil springs in my Camp 9s. It may seem counter intuitive, but after almost doubling the recoil spring rate, the Camp 9s still extracted and ejected flawlessly with with everything from lightly loaded factory and handloaded ammo to very energetic factory and handloaded ammo. Anyway, I suspect the S&B primers may be the reason for the pressure signs. BTW, don't remember if you said you're using a chronograph or not. Valuable tool for a handloader IMHO.

[jetinteriorguy]

I'm shooting indoors and chrono's aren't allowed. I have a feeling it's the primers, they are brass color, not chrome like most hard primers. I should be able to rework my loads this weekend and get to the range on Monday to try again. I'm going to ask on the forum if anyone has had this experience with S&B pistol primers.

[Stats Shooter]

I have never used SB primers, but I have had loads that I attempted to work up using two different primers at the same time. In my AR-10 I was using federal 210M and CCI-BR2 and the federal primers flowed to fill the pocket while the CCI's were still round....This occurred at 4k psi below MAP.

[highrolls]

briandg: " When you look at case blowout photos, nothing even remotely looks like mine."

And because of that and your descriptions, a photo of that would be a "one-of" internet classic. Murphy's law tells me that you may not have such a classic photo of it ?

ShootistPRS: "In the last 45 years of reloading I have never had cases shorten regardless of their shape."

I would normally agree with that except for the multiple reload test on 9mm I discussed, where I was specifically looking and measuring everything I could think of. My experience is a few years less than yours, but I have not had a reason to ever trim any pistol case, and I gage check all of them after the resize operation. I will concede that the straight walls like 357 magnum and 44 magnum would benefit from a trim but even if the gage shows a slight overlength there, I simply give those the extra roll crimp they deserve. Which means that I further concede from your entire post that I believe you are a more consistant shooter than I and that you are discussing something which helps your accuracy. For me, the magnums (44 in particular) can use extra crimp since I have never eliminated all the "flinch" when I shoot them. Yeah, Shootist, I am a wimp. I still flinch on the big Mags.

rock185: Entire post is extremely thought provoking. So much that it took me right back to the prior post.

jetinteriorguy: "even at the lowest level of 5gr I had primer flow, tried 5.2 and saw a substantial increase so I shut it down."

This is an excellent example of how any reloader should be conditioned to react FIRST, to anything that concerns you.

Mississippi: "and the federal primers flowed to fill the pocket".

I also agree entirely with rock185. The key for my own understanding is the use of the term "primer flow".
For me, this implies what I would describe as primer flattening, losing its round edge and leveling with the pocket brass edge, or Mississippi's simpler statement above. I have seen this in rifles, but never in a pistol case. What I see in pistols is a flatter than normal primer base which certainly changes the primer look, but not like a truly flattened-across-the-hole primer. With a magnifying glass, I can still see a slight rounding to the primer below the flat area. I see this most with "reduced loads" in revolvers, where the primer pops back, then the case slams back reseating the primer against the revolver receiver. But how do you really know ? Lets talk about "low pressure" signs.

What I usually see with the starting range in pistol load test, (and my argument for clean, not blackened cases), is the slight blow-back marks around the neck of the case. These should gradually disappear as the test load increments. (And usually the flatter than normal primer base will disappear with the blow-back marks.) Now if this does not happen, then I would have to go with rock185 and Mississippi on changing primers. Reading pistol case pressure signs is hard because they are minimal and can be easily argued over. Plus it is usually a sample of ONE. That is why I use multiple guns for load development. One can be a fluke. Three or more is STATISTICS. (BIG GRIN)

[briandg]

Of course I have photos, a handful of good, close up shots, but the quality is not great. I sent three to your listed email. You can send any comments through pm or email.

[ShootistPRS]

Highrolls,
I would never call anyone but myself a wimp. Right after I got my 357 I developed a flinch - a bad flinch. Once I recognized it I started dry fire practice, loading inert ammo mixed with good ammo, and firing at very close ranges. (ten feet) I practiced with slow moving wad-cutters and worked my way up to full magnum loads. When I could put six shots through the same hole I moved the target back a yard and fired until I could keep them in one ragged hole. I kept moving the target back until I could keep my rounds in a one inch group at 25 yards. Then I practiced at 50 yards, 75 yards, and finally 100 yards. (all standing shooting off hand (no support)) Thanks to Hunter's Pistol Silhouette I got a lot of practice and the "instant gratification" of targets blown off their stand. It took a couple of years but I learned a lot about the "dreaded flinch", what caused it, and how to cure it. Building a flinch is natural no matter how big or small you are. It is the body's natural reaction to recoil and muzzle blast. Your body learns that every time the trigger finger is moved rearward when aiming a gun it gets a mechanical kick and the brain connects it to the loud noise that happens at the same time. The muscles try to resist the kick and the noise causes the eyes to blink. I spent a lot of time at the range telling my self out loud that it was not going to injure me and could shoot relaxed and without fear. Dry fire reinforced the fact that pulling the trigger did not always result in a kick ad a loud noise and in fact most of the time nothing happened. I practiced balancing a dime on the front sight while pulling the trigger in double action. (the dime was laid across the sight not standing it on edge)

You can get rid of your flinch too by doing the same things. It does require a real desire (need) to cure it and about twice the amount of dry fire practice as you spend shooting live fire. Dry fire is also used to get a sight picture quickly and how to breathe and control your trigger. It takes you back to the basics;
Breathe, relax, sight alignment on the target, trigger control and follow through. In this case it is OK to talk to yourself positively and reward yourself when you do it all right.

[briandg]

At one point after brain surgery I "forgot " how to fire a revolver single action. I couldn't do that little tiny tick of a pull. Everything I had used for a while had either a long lead up or I was using my revolvers DA.

I'm good at da. I could roll through the cycle and was accurate. The problem seemed to be isolating that small movement and doing it. I'm still not working it well.

[briandg]

Sixty years ago people talked about the .45 and .357 being high recoil rounds, then .44, now,the cannons are in fashion.

Those guns are still big shockers. At the time of the creation of the .357, I feel that most people had used nothing bigger than a police .38. Retired military would have experience with .45, even so, many people loaded them down to be "softball" loads.

The .357 is an intense load with brisk recoil and a heavy blast. Many shooters without extensive histories will find it hard to shoot.

I have no desire to fire anything more powerful than a .44.

[jetinteriorguy]

I guess what I meant by primer flow is that the primer was quite literally flowing into the firing pin hole in the breach, not just a little cratering. And not just a little but a pretty substantial amount. I thought the primers were flattening out but upon closer inspection I see that the S&B primers are quite flat when seated. The cases were only slightly discolored around the rim so they seemed to be sealed ok, at least as good as any other loads I've used in the carbine. I have noticed though that this gun does just seem to shoot dirty, which I've always attributed to it being a blow back design. Well, I'll just keep messing with it until I get it figured out. After all that's part of the fun with handloading.

[GilaDan]

I have a JRC in 9mm. Have two Berettas (45acp and 40s&w) and a Hi Point 380. The JRC 9 is by far the most accurate. Put a sweet trigger in for a smooth and light pull.

Couldn't emphasize enough if you have not used Herco in 9mm loads you are missing one of the most accurate powders for 9mm. The JRC shoots a one inch group at 50 yards and 2.5 inch group at 100 yards using 4.7 Herco with a Lee 125.