What happens if you don't put enough powder in the case?

[sentry1]

I've been having one of those days...

I loaded up some .308 with CFE223 and 147gr FMJBT, in .5 grain increments from 45.5 to 47.5 grains... except that was the load data for 175gr SMKs.

The load data for 147gr (actually 150gr, that was the closest I could find in the Hodgdon database) was 48.4 to 51.5 grains.

What are the consequences of undercharging a case? Is it safe to fire?

P.S. At this point I'm not concerned about accuracy, I'd just use these rounds to break in the barrel some and get some brass that'll tell me the ideal specs for my chamber, if it's safe to fire.

 

[MAGUA]

I would have no problem firing them with that load.

 

[ksthomas]

Sentry1,

You've loaded up some very light loads, simple as that. Pull 'em, if you want to have a second go 'round, or just pull the trigger. Nothing hazardous here, just lower velocity than you were planning on.

 

[sentry1]

Thanks for the input guys. I'm going to fire em off, this was the last of my CFE223. That stuff is even harder to find than Varget, which I'm switching to after this batch anyways.

 

[40xs]

A general rule is stay within manual listings. You should be ok with the loads you mentioned, however, please do not adopt this practice with pistol cartridges as under charging cases with certain powders can be hazardous. Case in point is magnum cartridges and win. 296 or H. 110 should be loaded to within 90 percent of density,( check manual for exactness on this). To have too much space left in the case can raise pressures. I undercharged a .45 L.C. case with 4227 and was getting delayed discharging. I stopped immediately.

 

[sentry1]

I didn't do it intentionally, I was just having a day when Mr. Murphy was looking over my shoulder. For instance, when I went to fill my Chargemaster with the CFE223, I forgot to close the discharge spout at the bottom, so about a half pound of powder went all over my workbench. It was a FML day.

Now I'm going through my whole loading process andd adding poka-yoke (aka idiot-proofing) steps and labels so I avoid doing this again.

 

[sentry1]

Well, this is what happens:

First round jammed in the chamber, and of course I didn't have a cleaning rod with me to punch it out. Good thing I brought the AR15 out too, or that trip to the range would have been wasted.
The extractor ripped the rim right off the case.

So, from what I've read, too little powder in the case causes higher pressures. Did the pressure cause this case to jam in the chamber?

Ughh, I do NOT want to disassemble the other 39 rounds by hand with a kinetic puller. Guess I'll have to back order a Hornady collet puller and some collets so I can strip and reload the rest.

P.S. My scope was zeroed for M118LR at 200yds, and the 147gr FMJ bullet from this cartridge was 1" off the bullseye, so I guess the velocity didn't drop that much with this load?

 

[Unknown]

A really good piece of range bag kit for stuck cases is bronze brazing rod from a welding store. Because it is bronze, it is much softer than barrel steel. A 1 foot long piece of .25 inch works to knock out bullets or cases stuck in any bore bigger than .25 inch. And it is cheap!

 

[Name Enough]

I didn't realize nor did some others that an undercharge could be such a problem.

I had a round stuck half way down the barrel once on a 257 Weatherby Mag and got a bronze brazing rod from the welding supply shop and had to pound it out with a heavy hammer. Since then I pay very close attention to my charges and I inspect my cases after charging and if any look suspect the get re-weighed.

 

[Graham]

I wouldn't ever load light with spherical (ball) powders like CFE223, WW748, BLC(2) and the like: Pressure spikes can result at a reduced case volume.

 

[Powder_Burns]

Squibbed loads are especially fun in revolvers. My first foray into handloading consisted of developing a load for a .44 magnum, my first charges were too light and the first shot lodged the bullet in the forcing cone and pushed the case up against the recoil plate. Tapping the bullet back into the case with a range rod, vice grips, and a mallet was a very stupid idea but thankfully no one got hurt. The published minimum/maximum loads are good & safe guidelines to go by...

 

[ksthomas]

Sentry1,

Looks like there's something else going on here, and I think it's worth a little investigation. Undercharges with most medium burning-speed powders (single-based extruded powders, anyway) don't generally give any sort of pressure problems, and tend to function pretty well in such cases. There are actually a few that were specially developed to be used in such loads. Others, such as the very slow burning powders can and do give serious problems if they're underloaded. Known as Pressure Excursions or Secondary Explosive Effect, the phenomenon is well documented. As other posters here have mentioned, some powders are particularly sensitive to this sort of thing, and should NEVER be loaded below listed data. Winchester's 296 or Hodgdon's H110 (same powder) are the best known examples of this, and they are indeed very touchy about such reductions.

I'd be a interested in knowing a bit more about this, and how the rim managed to be damaged so badly. Any other damage to the case? Loose primer, or was it still firmly in place? That sort of thing. Anything more you can share would be educational here, to say the least.

 

[FLIGHT762]

I agree with Kevin, the jamming of the case in your chamber may be from an improperly sized case and has nothing to do with the lighter charge of powder. Do you have some way to measure your shoulder bump?

 

[sentry1]

Details:

It was a Mega Arms match barrel, about 50 rounds old, cleaned before I went out there, so I think it's safe to eliminate a cruddy chamber.
Seekins adjustable gas block at full open. If I had had a rod to punch the brass out, I would have tried turning the gas system down for the next round.
The case was originally fired in my 700 bolt gun, and was sized in an RCBS X-die (regular, not small base), set up to bump 0.0004" based on the brasss that came out of the MATEN.

As for the brass, the damage is exactly where the extractor ripped it off. It was stuck in there pretty good, and took 3 smacks with a cleaning rod down the barrel before it popped out.

The case is otherwise undamaged, and the primer is still firmly in place.

Let me know what other details I should examine.

 

[FLIGHT762]

Now that I know you shot it in a gas gun, my SR-25 doesn't like CFE 223. I tried a few loads and got excessive pressure with the Hodgdon published loads, even in my bolt guns, the Hodgdon data showed pressure signs. I used 46.0 of CFE 223 with a 175 Nosler OTM and the brass was mangled. The load was too hot.

I used 48.0 grs. with a 155 Nosler OTM and it wasn't too bad in the SR-25, but still showed a stout load.

I'm confused about your gas block. You said you were at full open, does that mean maximum gas or minimum? If it was maximum gas, I'd try it again with the gas turned down to bleed off more gas and go from there.

 

[sentry1]

I've loaded CFE223 for my AR15 and had no issues with pressure.

As for the gas block, yes by full open I meant maximum gas. I'd have turned the gas down and tried again that day, but I forgot to bring a cleaning rod to punch the barrel with.

At any rate, as soon as someone somewhere gets the damn .30 cal collets in stock, I'm going to pull these bullets, dump the powder and just re-do with Varget, and the right load data.

 

[Paladin2147]

If you stick another one, a little Kroil down the bbl. before you whack at it, will save you and the bbl. some work.

 

[The_FNG]

Well, this is what happens:

Secondary explosion effect?

 

[sentry1]

Secondary explosion effect?

What do you mean by secondary explosion effect?

 

[BuzzBoss915]

The term I am familiar with, concerning extremely light loads, is called detonation. Think of a case with ? 50 grain capacity and you dump 25 grains behind a heavy bullet. There will be lots of empty space under a loaded bullet. It's like a time delay, and you can't even predict what the pressures might be once it reaches critical mass, or whatever you want to call it? But, it could be enough to blow up the gun. As the others have said, stick with published data and match the charge weight with the correct bullet. In some cartridges, substituting a bullet weighing just five grains heavier can cause excessive pressure.

The other thing is, you mentioned using brass that was previously fired in your bolt gun. I hope you check over all length, (necks) so that you aren't causing a crimp on the bullet when it is chambered? BB

 

[The_FNG]

What do you mean by secondary explosion effect?

Secondary explosion effect

Basically it means the powder explodes instead of burning at a constant rate.

 

[sentry1]

I agree with Kevin, the jamming of the case in your chamber may be from an improperly sized case and has nothing to do with the lighter charge of powder. Do you have some way to measure your shoulder bump?

I ran all the cases through a FL sizing die, which I had set to bump .003"ish based off brass that I had previously fired in this gun.

I'm wondering if the culprit might be excessive gas in the system. I was using a heavy buffer when I had a 16" carbine barrel on this gun, and thought I'd keep it and just tune the gas system to work with it. However, I found that to reliably cycle both M118LR and M80 ammo, the gas block had to be fully opened with the heavy buffer, or it wouldn't cycle properly.

I've ordered a standard .308 carbine buffer, and I'm hoping that I can turn the gas way down. On that note, I've decided that the Seekins gas block is a crappy design. I have to take my handguards off to get at the adjustment screw, and I can't adjust the tension screw, period, because of the barrel shoulder behind the gas block seat.

A forward facing adjustment that I can access under the handguards would be a much more useful feature.

 

[P7id10t]

I agree with Kevin, the jamming of the case in your chamber may be from an improperly sized case and has nothing to do with the lighter charge of powder. Do you have some way to measure your shoulder bump?

I've seen this one in my 308 with too much powder. Case stuck, extractor ripped off the case rim, other pressure signs. A lesson not to push the max on my gun.
I've also seen improperly sized cases, where the bolt will not return to battery and not lock up.

 

[shoot4fun]

Oversized brass is most likely culprit. When reusing brass from other chambers it is difficult to properly resize for the semi-auto chamber without a small base die. Even then I really cam the press over on the FL sizing step to maximize bump and base sizing. The other culprit could have been oil in the chamber. I once bought a new Colt AR-15 and, in my rush to get some rounds thru it, did not clean the bore & chamber first. Stuck the very first round and was on my way home quickly.
Although the 147 v. 175 may have increased case capacity slightly I don't really think you are in detonation danger with the loads you built. Hodgdon tech support would know more about it than any of us here would. No offense to anyone here but I would trust only their answer. Did you ask them?

 

[sentry1]

Frankly I assumed Hodgdon's response would be : "We only recommend you use the published loads in our books and can not be liable for anything outside those bounds."

Not that I would blame them if they did, we live in very litigious times, but it does make it frustrating to try getting good info from anyone.

 

[Starvingboy]

I think I would look at improperly sized brass. I played around with an X-die for a while, and as long as I shot the ammo out of the same gun, no problems. Once I tried switching the X-die sized ammo to other guns, and the brass kept getting stuck in the chamber. Keeping track of which brass for which gun became a big hassle.

I eventually got a dillon trimmer, which has since made life much easier and bypassed the issue

 

[BuzzBoss915]

The above post illustrates where normal reloading practices have degraded. I have always kept my brass for a particular rifle separate and identified cases and loaded ammo with intentionally different brands and even bullet styles, since I once owned two 6MM at the same time. In no way did I ever attempt to shoot handloads developed for my Model 600 in my ParkerHale Mauser. And, it was easy, even the primers were a different color.

I suggest developing a load, or several loads for a particular rifle and making damned sure those rounds never are used in another gun. This is the basis, and the essence of custom handloading. If you don't maintain meticulous clean room standards, you might as well forget about the expense and the bother and just buy factory fodder. (no offense, of course, just calling 'em as I see 'em) BB

 

[sentry1]

Well, I went out again, turned the gas block waaaay down, and tried it again. Case didn't jam in the chamber this time, but here's what did happen:

If you look at the rim, you can see the indentation left by the extractor. So, this load is definitely a no-go. Fortunately, a local reloading shop (pfft, local... two hour drive each way), had .308 collets in stock, so I just got done pulling all the bullets and dumping the powder out.

Only problem now is I have 37 cases with a lot of powder still left in them. CFE 223 seems to be very clingy. I think I may just chuck this lot of brass out as the cost of a learning experience.

 

[armorpl8chikn]

TIMING! That is your problem. You turned the gas way up, snatched the rim off. You turned the gas down, no problems except nasty extractor ding. I am by no means an expert on gas guns, but I do know the pressure curve needs to fit within a certain spec. I deal with pump curves and believe it or not a slight parallel can be drawn. Even with the adjustable gas block this load is not within spec. I guarantee you this load would have been normal and mild in a bolt gun, just like Kevin said. You DID NOT mention in your initial post that it was a gas gun. I would not load any 270 for my FIL's Remington jammomatic, and you have illustrated the reason why. I have seen Jammomatics with broken extractors and this is how it happened. Once you break one in a Rem-oJam-o, you might as well use it for a mater stake. When you are dealing with some gas guns it is best to use published loads only. If you experiment , keep some spare parts handy.
I think you are wise to do as you have indicated and pull them, and go with a KNOWN load for a gas gun.

 

[scudzuki]

Oversized brass is most likely culprit. When reusing brass from other chambers it is difficult to properly resize for the semi-auto chamber without a small base die. Even then I really cam the press over on the FL sizing step to maximize bump and base sizing. The other culprit could have been oil in the chamber. I once bought a new Colt AR-15 and, in my rush to get some rounds thru it, did not clean the bore & chamber first. Stuck the very first round and was on my way home quickly.
Although the 147 v. 175 may have increased case capacity slightly I don't really think you are in detonation danger with the loads you built. Hodgdon tech support would know more about it than any of us here would. No offense to anyone here but I would trust only their answer. Did you ask them?

Interesting statement.
In my AR-15s I shoot almost exclusively reloads from range pickup brass, plus 4k once fired cases I bought recently.
I reload for my FNAR (.308) with range pickup brass.
All are run through a Lee FL die before reloading and I have never had a case stick in any of my ARs or the FNAR.
My buddies shoot my reloads without a problem, too, so there's a pretty good sampling of gas gun chambers there.

Joe

 

[sentry1]

I eliminated oversized brass as the culprit, as I used an RCBS FL die to size all the brass, and my 175gr loads with the correct charge worked just fine.

 

[scudzuki]

Well, I went out again, turned the gas block waaaay down, and tried it again. Case didn't jam in the chamber this time, but here's what did happen:

If you look at the rim, you can see the indentation left by the extractor. So, this load is definitely a no-go. Fortunately, a local reloading shop (pfft, local... two hour drive each way), had .308 collets in stock, so I just got done pulling all the bullets and dumping the powder out.

Only problem now is I have 37 cases with a lot of powder still left in them. CFE 223 seems to be very clingy. I think I may just chuck this lot of brass out as the cost of a learning experience.

Punching out the primers and tumbling/vibratory polishing them would remove the powder.
I have reused primers that have been punched before firing without a problem.
Compressed air with a little nozzle to go down inside the case mouth would likely do the same with even less work.

Joe

 

[FLIGHT762]

I found IMR 8208 XBR and Alliant AR Comp was easier on my brass and gave me good velocities with 155's,168's and 175's in my SR-25.