please share your (bad) experience using underpowered loads

[PrestoColumbus]

I have heard underpowered (not enough powder) loads can be as dangerous as overpowered loads

A few months ago I think I may have ruined my bolt with an underpowered load (225gr 300AAC with H110 powder in an AR platform). I think I had what’s called a “flash over/detonation” because the H110 is position sensitive and I didn’t have enough powder in it. I’m still trying to understand it

I’m trying to understand the risk/danger with underpowered loads.

I think I understand why overpowered loads are dangers (too much pressure and no where for it to go…) but I would think the only danger from underpowered loads is just the risk of having a squib

Are there some experiences that can be shared to illustrate what can happen?

I thank you in advance for sharing, I very much want to learn from others so I don’t repeat those mistakes and then I will be free to make all new ones :-o

[BJK]

I have never experienced it but I've heard it referenced as "detonation". I've never used WW296 below the suggested load data.

The only negatives I've experienced are butterfly fart loads in 9mm using other powders. They tested fine but in competition they gave random malfunctions. Annoying but not dangerous or anything that would damage the firearm.

But H110 and WW296 are noted for not being tolerant of low charges. But used as they are supposed to be used they are good powders (they are the same).

[Hick]

fundamentally, slower burning powders need to be loaded in such a way that the flame cannot reach all the powder at once-- like a rocket engine that burns from the base to the nose. If you go too low the powder can spread out in the case and expose too much to the flame of the primer-- bad news. So, if you want to go low you have to go so low that all the powder burning at once will be ok, like a firecracker. This is why low velocity loads often use small amounts of fast burning powder. The danger region is in-between those two. H110 is not a fast powder-- so underloading can be a problem.

[Petander]

I have a weak primer -story:

My friend,a shooting instructor,was test shooting a new factory load from a certain factory. Bad 100 m groups, sooty brass. Sort of weak ammo.

I was shooting a similar Tikka T3 Tactical 300 WM, he gave me some rounds to see how it goes with a suppressor, I had one mounted. After three mild feeling shots, bad accuracy and sooty brass I got a clear "CLICK-BANG!".

Could not open the bolt with any reasonale tool. My friend took my rifle to Sako, they had to remove the barrel to get the bolt and brass out.

Diagnosis: A bad batch of primers. A weak primer can start burning the powder a little, while moving the bullet, then you will have much more space for the powder to burn plus an obstruction-like situation. And all of a sudden it burns at once. Insane pressure.

Underpowered primers can be dangerous. This T3 Tacticsl is the only rifle that Sako has not managed to blow up with pistol powder bomb-charges.

[Gator 45/70]

To low of a charge and you're going to keyhole, Never keyhole!!!

If you're running a can then so much the worse damage you will get !

[JimB..]

There are stories of detonations from low powder charges, but to my knowledge they are not repeatable. I believe that most, if not all, are accidental dbl charges.

[Harter66]

I abandoned H110 for 45 Colts Ruger for these reasons ;
Mag primers , one more thing to stock .
Heavy crimps , that brass gets enough abuse without that .
Minor changes in OAL caused everything from throat jams with gas hiss to 250 fps rises in velocity . Like .05 gross length changes .

I use Unique to get my desired velocity with a standard LRP that is shared with several other cartridges .

Steel dies fixed a lot of the brass abuse but with brass being $35/100 and up I like to save it as long as I can .

At least if I do get a little pull or set back with Unique I don't have to worry about a blooper stuck or barely clearing and the next one going 1400 fps they all go 1000-1050 in the pistol and 1200-1260 in the carbine .

I tried really hard to like H110 ........

[PrestoColumbus]

To low of a charge and you're going to keyhole, Never keyhole!!!

If you're running a can then so much the worse damage you will get !


what is a keyhole?

[memtb]

A few years ago (about 1971 or 2), I was 18ish, and had just bought some yardsale (estate) reloading equipment. One of the items was an Ideal#55 powder dispenser. Never having used anything except the little dippers with a Lee Loader, no training from an adult, and no internet to learn from.....I thought that I had my #55 set-up properly. I was attempting to drop 2.8 grains Bullseye under my homegrown cast 148 WC’s. Yes, a 10 cavity Hensley & Gibbs 148 grain, flat-base WC mold was part of my estate sale purchase! :smile: I adjusted the #55, once getting a proper charge....never checking to be certain that it was throwing consistent charges.....it was not!

I loaded up a bunch, very excited about the speed at which I could now reload cartridges. I went to my local shooting spot, and proceeded to send bullets downrange....rapid-fire! Fairly early on, I got a very weak discharge, but being in the rapid fire mode....I touched-off another round! The recoil from that shoot was quite pronounced! I immediately knew something was not right, neither I nor the handgun were “worse for wear”! Thankfully, it was a Model 28 S&W, or the results may have been different. Apparently, I had a “squib” load.....followed-up by a good round! Knowing that something was right with the powder charge, I went home and experimented with the #55. As memory serves me, I didn’t realize/understand that there were 3 different sizes of charge bars and I was using only the largest....resulting in very inconsistent throws!

A lot was learned on that first outing with my new very used) equipment! memtb

[Mal Paso]

There are stories of detonations from low powder charges, but to my knowledge they are not repeatable. I believe that most, if not all, are accidental dbl charges.

Except in many cases there is just enough room for a single charge. In 44 Mag I could fit only 2 or 3 more grains more than max charge. I have never had anything but inconsistent combustion from light 296 loads but I can’t say for sure the SEE events are false.

[Mal Paso]

what is a keyhole?

Boolit doesn’t stabilize and tumbles going through the target sideways.

[Baltimoreed]

A keyhole is when your bullet strikes the target sideways instead of nose first so it leaves a hole in the target the shape of the profile of the bullet. Usually caused by bad rifling, leading, undersized bullet, too fast, too slow etc where the bullet is not getting stabilized so it tumbles instead.

[rockrat]

Had a Silhouette S&W 29 44 mag I had just purchased. Won a pound of AA#9 at the silhouette matches. Decided to try it in the 44mag with 295gr SWC boolits.
Had 13 pieces of new brass, so loaded what I thought would be a good starting load, weighed each charge and once done , inspected cases/powder in the loading block for uniformity, then proceeded to seat boolits.
Went PD hunting with friend. Took 6 shots to check for grouping, which did very well. Got our rifles out and shot a bit, took a break for some Gatorade and saw a few PD's about 100yds. Loaded gun with three rounds. First shot missed, second shot the same, third shot there was a pinkish flash, mild recoil, and I couldn't see the PD due to the top strap sticking up at about an 80 degree angle. Top 3 chambers of cylinder gone, but empty cases still in the gun, one split others bent. Friend heard something whizzing by him(probably cylinder piece) and the sight elevation piece that fits in the frame was down my t-shirt. Never found the sight.
Double charge?? Not a chance!!!
Load was way too light!!

[almar]

I abandoned H110 for 45 Colts Ruger for these reasons ;
Mag primers , one more thing to stock .
Heavy crimps , that brass gets enough abuse without that .
Minor changes in OAL caused everything from throat jams with gas hiss to 250 fps rises in velocity . Like .05 gross length changes .

I use Unique to get my desired velocity with a standard LRP that is shared with several other cartridges .

Steel dies fixed a lot of the brass abuse but with brass being $35/100 and up I like to save it as long as I can .

At least if I do get a little pull or set back with Unique I don't have to worry about a blooper stuck or barely clearing and the next one going 1400 fps they all go 1000-1050 in the pistol and 1200-1260 in the carbine .

I tried really hard to like H110 ........

I had a harsh learning experience with that powder as well. Improper crimps and standard primers in a 500 mag, the ignition was so poor that It pushed the bullet into the forcing cone and jammed the cylinder. It was a mess. That powder works well but it needs special care. I would say the same about lil gun. I use h110 in 300 AAC but I'm careful about it now. Its not my favorite powder I can say that much for certain.

[414gates]

Too little fast burning ball powder in a large case causes SEE, secondary explosive effect.

I had it in my 40S&W loads once that my son was shooting at the time, thankfully without a scratch to him.

Don't go below the minimum in the book. Some of the more recent load guides now mention the danger of an undercharge, none of the old books do.

If you need a reduced load in a pistol, use a flake powder, not ball.

For rifle, fill the empty space with dacron. I'm personally allergic to air in my rifle cases, but each to their comfort zone.

[Mal Paso]

AA2 is a ball powder with none of 296s problems. Ball/Sphere is just the process. Started as a way to make WW1 cannon powder usable in small arms. It is a less expensive, more flexible process.

[Polymath]

When I started reloading for 300 Win Mag, I started low on the powder charge. Got 8 hang fires and a couple of duds out the first box. Pulled the bullets on the duds and the powder was stuck, laying flat in the case. Solid and white. Looked like sugar. I scraped some out.
I increased the charge a few grains and used mag primers for the lower charges. That problem went away. Once I found my preferred load, I went with that.
Now, I do not always start with the least powder charge. I used to do that with some Dominion Powders (as per directions)
If it's a new or different powder you have never used before that is a good idea, however after you shoot some for a while you kind of get to know what it's doing.

[JSnover]

I've had three squibs and was able to pop them out easy enough. Luckily I stopped and investigated before anything else went wrong.
I try to keep my 'light' loads above 50% case capacity but when I load really light I double check everything before I seat the bullets.

[JimB..]

Except in many cases there is just enough room for a single charge. In 44 Mag I could fit only 2 or 3 more grains more than max charge. I have never had anything but inconsistent combustion from light 296 loads but I can’t say for sure the SEE events are false.
It is extremely difficult to prove a negative, so I also can’t say that the effect doesn’t exist, only that as far as I know nobody has ever been able to intentionally make it happen.

Rockrat believes that he had one with AA#9, but it was only one of 9 cartridges that he sincerely believes were as close to identical as he could make them. Wonder what the variable was. Could he have had a squib when he thought he missed the target on the second shot? Could he have double charged? Could a bullet have gotten set way back somehow? Could the powder have settled differently in the case that one time? That he went from shooting well to not shooting well makes me think there was something going on rather than just suddenly one bad cartridge. Wonder if the timing got way off somehow and he was spitting lead all over the place. Really hard to tell once the gun comes apart. Not saying that he’s wrong, just that there is no way to prove that it was caused by a light load.

[.429&H110]

FWIW
H110 is great powder for 44 mag in a superredhawk.
240gr keith boolit with mule snot, 1200fps is the ticket, accurate at 100 yards
I don't know why there is very little leading.
I have loaded 4721 44 mag with dozens of different loads
sometimes coating the bore with lead, testing at -40 to 115F
320gr bear loads to 180 gr "high speed" I have only shot one chronograph so far...
Certainly changing crimp changes everything else!

YMMV 20gr H110, no magnum primer, 240 grain keith boolit
will leave unburned powder in the brass. Goes plonk not bang.
IF that powder were to burn later, it would be bad.

H110 needs pressure to burn completely and -10% is not happening here.

Search this site for the difference between magnum primers and normal primers, would take all day to read it all.
18 yo kid showed me how to set up a bench, then showed me this forum.
Thank you!

[PrestoColumbus]

I had a harsh learning experience with that powder as well. Improper crimps and standard primers in a 500 mag, the ignition was so poor that It pushed the bullet into the forcing cone and jammed the cylinder. It was a mess. That powder works well but it needs special care. I would say the same about lil gun. I use h110 in 300 AAC but I'm careful about it now. Its not my favorite powder I can say that much for certain.

I’m thinking going forward I will use my H110 for supersonic with lighter bullets (300AAC !145gr), and I recently purchased some Accurate 1680 powder that i understand is better for subsonic heavy 220gr 300AAC bullets (specifically berry’s spirepoint)

[GregLaROCHE]

A friend and I were trying to get his suppressed M1A to shoot subsonic. The risk of a very light load, after some research, is that the small amount of powder may get ignited at the boolit end and not the primer end. With the powder burning backwards, pressure builds up towards the back end first and it’s like a shape charge and the pressure is not released by the boolit being released. That’s the theory and why people use fillers to keep all the powder back at the primer.

My friend didn’t think we needed filler, so we didn’t use any. It was his gun. We used a flake pistol powder. Never had a bad experience except the boolits would keyhole before we got subsonic. Maybe a faster twist could of helped. We were always chambering individual rounds and I made sure all the powder was tapped down so it would all be next to the primer.

[Rapier]

I have been running H110 in sub guns, ARs and TCs since JD Jones developed and introduced the Whisper. Never had a problem with sub loads using H-110 or 296 following JD’s directions. I run my 220g PCed cast with SRPs subsonic with JD’s published H-110 loads also run 160s in the 6.5 Grendel with H-110. Never had a problem in 40 years.

[Gator 45/70]

what is a keyhole?

Bullet smacks the target sideways !!!

[gwpercle]

Bullet smacks the target sideways !!!

I wonder why it's called a Keyhole ... I think Gator's terminology is better ...
Lets call them having ... a STS ... Smack Target Sideways !
STS sounds so tacticool and modern .:cool:
Gary

[PrestoColumbus]

I wonder why it's called a Keyhole ... I think Gator's terminology is better ...
Lets call them having ... a STS ... Smack Target Sideways !
STS sounds so tacticool and modern .:cool:
Gary

yep, STS it is

[Mal Paso]

STS Space transportation system was the space shuttle. :Fire:

[BJK]

It's been called a keyhole for billions of years. Get used to it.

[Handloader109]

I couldn't get H110 to work in my 300 BO pistol worth a darn. I'd say get powder made for that round.. I've seen CFE BO several times with very little else on the shelves. It works well. I have a bunch of H110, using it in 22tcm.

Sent from my SM-G892A using Tapatalk

[Finster101]

Hogdon offers load data for .300 BO subs using H-110. Most of them call for a magnum primer.

[Gator 45/70]

I couldn't get H110 to work in my 300 BO pistol worth a darn. I'd say get powder made for that round.. I've seen CFE BO several times with very little else on the shelves. It works well. I have a bunch of H110, using it in 22tcm.

Sent from my SM-G892A using Tapatalk

You talk a gorilla of a powder to meter, CFE-BO is right up there.

Myself I use about 16 grains of H-110 to push a Hornady 125 ballistic tip super-sonic out of a 16'' barrel. My pig load.

[JSnover]

I wonder why it's called a Keyhole ...
Gary

Because it looks like a keyhole, let's not complicate things.

[BJK]

I'm using WW296 (aka H110) to push a Maker 85 to 2300 fps out of a 10" barrel. It works fine. But I wouldn't use it for subsonic loads. It would be totally unsuited for that unless it was (maybe) in a manually operated action. Even then it wouldn't be my first choice.

[fixit]

My experience wasn't really with "underpowered" loads.... But that was what I was moving towards. I have a few sub cartridge adapters, 2 for 7.62x54r and two for. 303 British, one of each for 7.62x25 and 32 ACP. I was shooting some 32 ACP from the. 303 adapter, going as quickly as possible, because I planned to reload them with heavy for cartridge boolits for cat sneeze shooting, when I heard a strange report..... Following due diligence, I stopped, cleared the gun, and realized I'd experienced a squib. With more examination, I found the barrel had split at the band for the front sight, and upon removal of about 3" of barrel, I found there to be 5 bullets in the barrel. This particular rifle has considerable" windage" in the barrel, measuring about .317, and the small bullets of the 32, plus the blow by, plus my hurriedness, created a perfect Storm of errors. Thankfully, this particular SMLE was already severely bubba's when I got it, so it just continued to be a project rifle!

[JonB_in_Glencoe]

STS Space transportation system was the space shuttle. :Fire:

and...

STS (Seville Touring Sedan) ......Cadillac ! :Fire::Fire::Fire:

[reddog81]

H110 works well for me in subsonic and supersonic BLK loads. There’s plenty of load data for it and it’s one of the more common powders used. I’m sure millions of rounds have been sent down range with it.

What charge weight were you using, what happened while shooting and why do you think the bolt is ruined?

[hoodat]

I come down in the camp of using VERY fast burning and easy igniting powders for underpowered loads.

I ALWAYS use a flashlight to verify no double charges. I also never use case fillers.

The older Lyman books such as #45 and pre, are your friend for published data for these loads, and the common and proven powders are usually the standard pistol powders. I don't see H110/W296 list among them. That powder has always had a rep for unreliable ignition and incomplete burn at low pressure. I do often see 4227 listed for light loads. jd

[Larry Gibson]

I have heard underpowered (not enough powder) loads can be as dangerous as overpowered loads

A few months ago I think I may have ruined my bolt with an underpowered load (225gr 300AAC with H110 powder in an AR platform). I think I had what’s called a “flash over/detonation” because the H110 is position sensitive and I didn’t have enough powder in it. I’m still trying to understand it

I’m trying to understand the risk/danger with underpowered loads.

I think I understand why overpowered loads are dangers (too much pressure and no where for it to go…) but I would think the only danger from underpowered loads is just the risk of having a squib

Are there some experiences that can be shared to illustrate what can happen?

I thank you in advance for sharing, I very much want to learn from others so I don’t repeat those mistakes and then I will be free to make all new ones :-o

What you had or were close to having was an SEE (Secondary Explosive Effect). Some refer to it as a "Pressure Excursion".

Smokeless powders do not "detonate" in cartridges, they burn. How and when they burn is the problem.

The cause of SEE is well understood since the advent of piezo-transducer and strain gauge pressure measuring since the '80s. There is an excellent explanation that was published in a Handloader article which I have posted here numerous times. An SEE can easily be reproduced pretty much "on demand". Being able to measure the pressure, observe the Rise to peak pressure and the time pressure curve/trace has allowed me and others to observe the potential SEE before it occurs.

All of the old theories (which are/were not reproduceable) may have sounded good but they were not the actual cause of an SEE.

What actually occurs is a series of conditions (not all the conditions need be present) lead up to the root cause of an SEE....a bore obstruction. Seldon does an SEE occur with just one or two shots. It usually will occur with shots three through 10 +/-. In the case of your AR with that reduced load of H110 the force of the primer pushed the bullet into the probably already fouled throat/leade/bore where it stuck because the powder had not yet begun to burn. Then the powder began to burn and it reached excessive pressure before the bullet began moving fast enough to lower the pressure from the expansion ratio as the bullet moved down the bore. SEE's do occur with cast bullets but usually the bullets begin moving because cast are softer than jacketed. Fortunately for you, the cast bullet began moving before the pressure really got high.

All this occurs very quickly, in milliseconds, and is usually not noticed. However, sometimes a "click/bang" effect is noticed. That is an omen of potential SEE and any time a click/bang occurs you should stop using that load.

Over the last 50+ years I have been directly involved with a couple SEE's that actually did destroy the firearm. I also have been involved in several probable SEE's and have investigated others that were found to be probable SEEs. I also have on several occasions while pressure testing loads observed the buildup of pressure that leads to SEEs. I stopped testing before the SEE occurred.

[Larry Gibson]

I’m thinking going forward I will use my H110 for supersonic with lighter bullets (300AAC !145gr), and I recently purchased some Accurate 1680 powder that i understand is better for subsonic heavy 220gr 300AAC bullets (specifically berry’s spirepoint)

An excellent course of action......

[Larry Gibson]

There are stories of detonations from low powder charges, but to my knowledge they are not repeatable. I believe that most, if not all, are accidental dbl charges.

Smokeless powders do not "detonate", they burn. I agree that most "blow ups", especially with reduced loads, are caused by double charges or inadvertent over charges.

[Larry Gibson]

Had a Silhouette S&W 29 44 mag I had just purchased. Won a pound of AA#9 at the silhouette matches. Decided to try it in the 44mag with 295gr SWC boolits.
Had 13 pieces of new brass, so loaded what I thought would be a good starting load, weighed each charge and once done , inspected cases/powder in the loading block for uniformity, then proceeded to seat boolits.
Went PD hunting with friend. Took 6 shots to check for grouping, which did very well. Got our rifles out and shot a bit, took a break for some Gatorade and saw a few PD's about 100yds. Loaded gun with three rounds. First shot missed, second shot the same, third shot there was a pinkish flash, mild recoil, and I couldn't see the PD due to the top strap sticking up at about an 80 degree angle. Top 3 chambers of cylinder gone, but empty cases still in the gun, one split others bent. Friend heard something whizzing by him(probably cylinder piece) and the sight elevation piece that fits in the frame was down my t-shirt. Never found the sight.
Double charge?? Not a chance!!!
Load was way too light!!

Classic SEE; fired the first 6 shots ok. That fouled the throats/forcing cone. Then the fouling probably hardened in the warmer weather while you shot PDs with the rifle. Then on the third round the powder was probably at the base of the bullet from the recoil of the first 2 shots. The primer flash pushed the bullet into the forcing cone where it stuck sealing off the barrel/cylinder gap also. Because the powder was also pushed forward into the cylinder throat it didn't ignite properly but smoldered but when the bullet stuck it started to burn. Before the bullet could get moving again the pressure reached a catastrophic level which the cylinder could no longer contain.

It does happen......

[PrestoColumbus]

What you had or were close to having was an SEE (Secondary Explosive Effect). Some refer to it as a "Pressure Excursion".

Smokeless powders do not "detonate" in cartridges, they burn. How and when they burn is the problem.

The cause of SEE is well understood since the advent of piezo-transducer and strain gauge pressure measuring since the '80s. There is an excellent explanation that was published in a Handloader article which I have posted here numerous times. An SEE can easily be reproduced pretty much "on demand". Being able to measure the pressure, observe the Rise to peak pressure and the time pressure curve/trace has allowed me and others to observe the potential SEE before it occurs.

All of the old theories (which are/were not reproduceable) may have sounded good but they were not the actual cause of an SEE.

What actually occurs is a series of conditions (not all the conditions need be present) lead up to the root cause of an SEE....a bore obstruction. Seldon does an SEE occur with just one or two shots. It usually will occur with shots three through 10 +/-. In the case of your AR with that reduced load of H110 the force of the primer pushed the bullet into the probably already fouled throat/leade/bore where it stuck because the powder had not yet begun to burn. Then the powder began to burn and it reached excessive pressure before the bullet began moving fast enough to lower the pressure from the expansion ratio as the bullet moved down the bore. SEE's do occur with cast bullets but usually the bullets begin moving because cast are softer than jacketed. Fortunately for you, the cast bullet began moving before the pressure really got high.

All this occurs very quickly, in milliseconds, and is usually not noticed. However, sometimes a "click/bang" effect is noticed. That is an omen of potential SEE and any time a click/bang occurs you should stop using that load.

Over the last 50+ years I have been directly involved with a couple SEE's that actually did destroy the firearm. I also have been involved in several probable SEE's and have investigated others that were found to be probable SEEs. I also have on several occasions while pressure testing loads observed the buildup of pressure that leads to SEEs. I stopped testing before the SEE occurred.



You are absolutely correct sir.

Going back thru my records…. this was July 2021

I had several rounds loaded with 6.7gr H110 (looking back that was kind of stupid but at the time i didn’t know all this) and 225 gr Berry’s Spirepoint .308 in a 300AAC cartridge with small rifle (not magnum) primer

6 rounds fired over chrono (~800-850 fps)
afterwards I did observe some strange scratches on the hulls (debris in chamber?)
none cycled the rifle (DPMS rifle with 16” barrel)

round #7 was the problem
- i felt a sharp recoil
- BCG did not cycle into the buffer
- smoke/soot coming out of every place it could find, even found soot shoved down into the magazine
- myself and several others tried in vain to pull the bolt back but could not extract the spent case
- we did record a reading on the chrono for the boolit in the 700 range (was lower than expected)
- gunsmith had to remove barrel to get the case out, found bolt face was disintegrated and had to replace that
- i still have not attempted to fire this weapon again as i think the chamber is damaged and i want another gunsmith to look at it

bottom line: i’ve learned a value lesson that i’ll never forget. i’m lucky i didn’t end up seriously injured. and much better/cheaper to ruin my rifle and buy new one than to end up in the hospital

thank you for sharing your opinion from the technical viewpoint. it very much lines up with my experience

There’s a saying we have, “sometimes you see something so stupid you know a Marine has to be involved…” [smilie=s: I’ll take the hit on this one! (well, i already have)

[KCSO]

Not mine but... My ex son in law borrowed my smith 5906 and went plinking with a friend who whipped up some ammo for him. The third round was a squib lodged in the barrel and number four fired quickly bulged the barrel about midway and ruined the barrel and was absolute heck to remove without damaging the slide. Then he took my daughters Charter snubbie and fired some more of the defective rounds and blew out the side of the cylinder. Then he got drunk and gambled away all their money, but that is another story.

[megasupermagnum]

"I have heard underpowered (not enough powder) loads can be as dangerous as overpowered loads'

No, underpower loads are WAY more dangerous than overpower loads. Obviously if you do something extremely dumb, you can over charge a cartridge to failure. You could probably load enough Unique in a 44 magnum to blow up the gun, but I still wouldn't bet money on it. Using sane powders like Bluedot, 2400, H100, etc. you would have to try your absolute best to blow up a 44 magnum. This carries over to most any cartridge's, at least for modern guns.

On the other hand, look at the plethora of ways in this thread underpower loads can ruin guns, even with experienced loaders have. My only issue was using very light charges, ended up double charging one. Thankfully a double charge was still well under a max load. Light loads are one thing, but the super light poof loads are not something to dink around with. They are serious business, way more dangerous than over charges of regular powder.

[Woodcarver]

I watched a gent blow up a beautiful nickel plated Colt 45 SAA with an undercharged round at a SASS match in the late 90s. IIRC, his "standard" load was 4gr of either Titegroup or Trail Boss under a 250gr cast FP. As we were counting hits, and he was a decent shot, we know the first round went down range. Then his second shot sounded "funny". The RO heard it and immediately called cease fire.
The top strap was severely bowed. The top of the cylinder on either side of the chamber fired was gone. The other live round was squeezed by the cylinder distortion and the bullet was wedged against the frame. The fired chamber had wedged the bullet partially into the forcing cone and blew the sides into the adjacent chambers. We think that is what blew the tops off those chambers.
He pulled about 10 bullets from his ammo supply and found several that only had about 3-3.5gr of powder. He used a progressive. At 4gr, he was below the recommended charge; at 3-3.5, he was way below. Trying to cut recoil down to improve times cost him a $1600 Colt.
Smokeless powder does burn, but when all of it burns virtually instantaneously, that is a detonation.

[pmer]

It seems to me that a lot times when this happens we're working on the edges of what a cartridge is designed for. I was doing this with a 458 Lott and 45-70. I started thinking why am I trying to turn a 458 Lott into a 45-70 and why am I trying to turn a 45-70 into a 45 Colt by using reduced loads.

I got rid of the Lott and switched powders in the 45-70 to medium speed extruded like IMR 3031 and got rid of the snappy recoil from 2400 and #7. And when I think I want "reduced" big bore performance I use Blue Dot in a 44 Mag. carbine.

I never looked back. :Fire:

[Finster101]

You are absolutely correct sir.

Going back thru my records…. this was July 2021

I had several rounds loaded with 6.7gr H110 (looking back that was kind of stupid but at the time i didn’t know all this) and 225 gr Berry’s Spirepoint .308 in a 300AAC cartridge with small rifle (not magnum) primer

6 rounds fired over chrono (~800-850 fps)
afterwards I did observe some strange scratches on the hulls (debris in chamber?)
none cycled the rifle (DPMS rifle with 16” barrel)

round #7 was the problem
- i felt a sharp recoil
- BCG did not cycle into the buffer
- smoke/soot coming out of every place it could find, even found soot shoved down into the magazine
- myself and several others tried in vain to pull the bolt back but could not extract the spent case
- we did record a reading on the chrono for the boolit in the 700 range (was lower than expected)
- gunsmith had to remove barrel to get the case out, found bolt face was disintegrated and had to replace that
- i still have not attempted to fire this weapon again as i think the chamber is damaged and i want another gunsmith to look at it

bottom line: i’ve learned a value lesson that i’ll never forget. i’m lucky i didn’t end up seriously injured. and much better/cheaper to ruin my rifle and buy new one than to end up in the hospital

thank you for sharing your opinion from the technical viewpoint. it very much lines up with my experience

There’s a saying we have, “sometimes you see something so stupid you know a Marine has to be involved…” [smilie=s: I’ll take the hit on this one! (well, i already have)




That load is way under Hogdon's starting load. I have loaded and shot many subs using the published data.