Pressure and Slide Function

[sureYnot]

Is it possible to have high pressure and not work the slide on an auto?

Here's the situation:

356-125-2R
COAL: 0.985

I'm loading heavy (125gn) in a .380. Found data in lyman 44 for 121gn. Red Dot start charge is 1.7 and max is 2.0. I worked up from 1.6 to 2.0 in 0.1gn increments. The lightest loads left the fired cases in the chamber. 1.9 still had some stovepipes. 2.0 cycled every time but didn't lock back the slide on the last round. Concern is that I may still get occasional stovepipes. I only tested 6 of each load.
Logically, based on what I know, (which is basically nothing, compared to some of you guys) I'm a ways off from reaching high pressure. In theory, I should be able to safely keep going up 0.1gn until the slide locks back and still maybe have some wiggle room.
Thing is, this is the first time I've felt any need or desire to go above published max (could only find anything close in this one manual) and it seemed like a good time to check in with some experts before proceeding.

[sigep1764]

What pistol are you loading for? I load the Lee 105SWC in 380 with 1.8-2.0 grains of Red Dot and its still snappy. Lyman 49th says 356242 at 120grains at .980 has a max of 2.1 grains of Red Dot. Use at your own risk.

[Greg S]

If the gun is new and the action is tight and hasn't been worn in yet, cycling will improve after break in and may fix your problem. For now, try a slower powder.

The heavier bullet might be too slow to develop enough slide velocity to reliably function without going over.

[44Blam]

Red dot is pretty fast powder. You might need a slower powder. I've got a cz52 and it needs a slower powder than most pistols of similar caliber. I tried unique and I was getting pressure signs in my primers by the time the action worked. But if I use a2400, it cycles even with reduced loads...

[iplaywithnoshoes]

You can have a pressure spike and have stove pipes. That pressure spike or plateau ideally needs to last long enough to work the slide, let alone fire form and expand the case completely.

If the case (or gun for that matter) is that sensitive to such a narrow range of powder charges and is considered dangerous or unsafe above 2.0gr. I would probably look for a different load. I cannot even guarantee that your powder measure variation is working safely within that range.

[Der Gebirgsjager]

Like the man said, "What pistol are you loading for?" If it's a blow back design, like most .380s are, and if it's in mechanically good condition, you have to balance the load vs. the strength of the recoil spring. Where the "mechanically good condition" part comes into play, is whether or not your hold open device is working properly. Once the slide hits the rear of it's cycle and the magazine is empty the slide should remain to the rear. It should be noted that some pistols lack this feature. Assuming yours has a hold open device that automatically comes into play when the magazine is empty, and that it's functioning properly, then your load is weak. Try a different powder, if you feel that you're reaching the maximum and the slide won't lock back. How does it work with factory ammo?

[sureYnot]

It's a glock 42. Less than 500 rounds through it. Factory rounds lock the slide. The 95 jhp i've loaded lock the slide.
No signs of pressure yet. But 2.0 is max listed for as close to this bullet as I can find and QL says 2.2 is over pressure.
Also per QL, not all of the powder is burnt before exiting the barrel. So I'm not sure how a slower powder might help. Pressure curve for RD 2.1 and Unique 3.0 is almost identical.

[JBinMN]

Do you have a chronograph?
Testing those 2.0 gr. RD for velocity, may help with determining pressure in THAT firearm. IOW, if the load data says you are reaching close to the 21,500 that is the recommended limit for a .380 Auto by the velocity of, for example 800fps, but you are only reaching an average of 720fps, perhaps you are not reaching or exceeding the 21,500 in THAT firearm.

Of course, you have to consider your bbl. length as compared to what they are using for testing( I.e.- are they using a Universal receiver with a bbl. longer than your bbl.?, etc..)

Regardless, I understand you are trying to use RD as the powder, but I would suggest that rather than exceeding the load manual data limits, or "before" you try it, work up some loads with other similar powders you might have, that do stay within the load data limits & see if you get the same results. (A burn rate table may help choose, if you do not know what might be similar enough, but Titewad, Ramshot comp., 700X, 800X, Clays, & Bullseye are just a few that are very close to burn rate of RD. If you have some of those powders already , then it is not much trouble to try them. https://www.hodgdon.com/wp-content/u...rate-color.pdf )

If you do get the same results working up other similar powders, then it may just be that the firearm is still too new & the recoil spring is stronger than what the loads can compress & it will take more time & firing to reduce the effort to compress the spring.

I am not one to recommend anyone going over the max. listed load data, so i will not advocate you doing so.

All of this is At Your Own Risk. It will be up to you to decide if ya want to "push the envelope", as is sometimes said. I am just suggesting you try other options before you "test those waters", anyway, for Safety sake.


G'luck! & please share what you end up deciding to do.

[JBinMN]

I went & looked at just a few of my reloading manuals. Not all , but a few. Most of the ones that show pressure for loads for the 120+/- at the max. suggested loads show them at around 15,800 CUP. The max pressure SAAMI is at 21,500, if I am not mistaken, so you would have just a little wiggle room, but in such a small case pressures rise fast. i have .380 rounds loaded for my .380, using Rd, Clays & something else( I would have to check, but thinking 700xor 800x) on my shelves that have not been tested yet for how they work or chrono'd, but when the weather warms I will be out doing that to see how mine does with them.

I am including in this post a page from a Loadbooks USA that has the 125 gr. listed & the powders RCBS tested, but it doesn't not show the pressures. Going from the other manuals that do list the pressures & similar powders the pressures in those other manuals do not show any higher pressure than 15,800 CUP.

You will, once again, have to make your own determination on if you wish to go higer than MAx. listed.

Here is the data page. :

You may have to increase the size in your browser, or download & magnify to read it. Sorry, but that is about the best I can do without chopping into smaller size for magnification with the camera on the phone.)

I hope i might have been of at least some help here. If not, oh well, I tried anyway.

[sureYnot]

Thanks everyone. JBinMN, chrony is on the list of things I want badly but hasn't made the "need" list yet. Getting closer though. There have been a few times I wished I had the data it could provide.
Seems the thing to do is not try anything fancy. Appreciate the input from everyone.

[kevin c]

Is it possible to have high pressure and not work the slide on an auto?

...

Thing is, this is the first time I've felt any need or desire to go above published max (could only find anything close in this one manual) and it seemed like a good time to check in with some experts before proceeding.

A common 40 S&W USPSA major power factor load of a few years ago (when the PF floor was actually higher than it is now) was a 200 or 220 grain bullet over regular Hodgdon Clays. The goal was the softest felt recoil and fastest sight recovery that would still cycle the gun. Even with the recoil spring weight down to 11 or 12# versus the standard 16, the guns sometimes wouldn't cycle, and even with the small charges needed, the pressures were still so high that bulged brass, flattened or pierced primers and blown out cases were not uncommon. The loads were definitely way over recommended, but some folks push the envelope for any perceived advantage.

[sureYnot]

Not that I'm recommending it, but thought I'd let y'all know what I did. Loaded 5 each at 2.1 and 2.2. Put one at a time in the mag. Fired the first of each with my off hand. (It's already all screwed up, with crooked fingers so no great loss if a couple disappeared.) 4 out of 5 of the 2.1 locked back the slide. All five of the 2.2 locked back the slide. No signs of high pressure, but I don't have any fancy equipment. Can only examine the brass/primers. I don't have the guts to test 2.3. So, the load will be 2.0 or 2.1. Probably 2.0 as what's the point of going any hotter to get slide lock if the slide doesn't lock EVERY time? It's the wife's gun. I won't have her shooting 2.2 unless I've fired several at hotter levels. If it were mine, I wouldn't do any of this foolishness. I'd just load 2.0 and learn how to count to 6 so I know when it's empty.

[JBinMN]

Thanks for returning & giving an update!


I do not know if you took it into account, but some powders are Temperature Sensitive and another thing to remember is that if you were testing in , let's say, 20F temps & the firearm & ammo was at that temp for a time to get colder than the 65-70 or so degrees F. that most components mnfrs use for testing their components, you may not be getting the pressures that you might in warmer weather, and if the components were warmer at the time of shooting the rounds.
( think about if they were at about room or heated vehicle temps, or did they sit in your vehicle & got cold for a while before you shot them.)

Cooler ammo usually means less pressures, and since we are in MN and it has been relatively "brisk" outside, you should likely keep that type of info in mind as the temps warm...

Just some things to consider.


If I remember, I will test out some of my .380 rounds when it warms up more using the chrony & also using RD & will share the info here about what I find here...

Caveat is.. "If I remember."


G'Luck! & Be Safe! and... Be warm!

[BigAlofPa.]

I load .380 with titegroup. It has been serving me well in all 5 of my .380's. My .380 1911 has the stiffest recoil spring and it works well.

[sureYnot]

JB, I didn't give the pistol or ammo a chance to get cold. Circulation in my hands is junk.

BigAl, I really like the titegroup too. Can't find an 8# jug for $140 out the door though. That's why I started playing with this stuff.

Sent from my XT1710-02 using Tapatalk

[JBinMN]

JB, I didn't give the pistol or ammo a chance to get cold. Circulation in my hands is junk.

BigAl, I really like the titegroup too. Can't find an 8# jug for $140 out the door though. That's why I started playing with this stuff.

Sent from my XT1710-02 using Tapatalk

OK. Well, I wanted to let ya know about the Temp Sensitivity, if it might have been something to consider.


G"Luck!

[Larry Gibson]

sureYnot

The max loads listed are for blow back operated semi autos as Der Gebirgsjager stated. You have a recoil operated pistol which requires a greater recoil impulse to operate.....just as you've found out. I suggest you go with the load that just functions the action reliably. It is not over taxing the Glock.

[EDG]

You can make some guns and load combos malfunction just by limp wristing the gun when you fire it.
Make sure to use a firm grip.

[JonB_in_Glencoe]

Like 44Blam suggested, you might want to try a slower powder, especially with that heavy for caliber boolit.
I use Power Pistol in 9 MAK (9x18) which is a similar sized case as 380auto

[sureYnot]

sureYnot

The max loads listed are for blow back operated semi autos as Der Gebirgsjager stated. You have a recoil operated pistol which requires a greater recoil impulse to operate.....just as you've found out. I suggest you go with the load that just functions the action reliably. It is not over taxing the Glock.

Thank you, Mr. Gibson. I failed to catch what Der Gebirgsjager was throwing, earlier. I hope you don't mind a slightly off-track question...Is the same true for other small caliber pistols that are/were also produced in a blow back configuration?
Thank you to all contributors. To clarify...I'm not looking for input on how to make this pistol work. I've done that. What I'm looking for, is an answer as to whether or not I can get what I want with this powder and boolit whilst keeping most of my fingers and all two of my eyes. Choosing between eyes would be difficult as my left is stronger, but I'm right-handed. I have a few garbage fingers, so that's why I'm ok with only "most" of them.
I did some digging around and found that there are lots of folks claiming they can't get reliable function from this thing until at or near max loads. Couple that tidbit with statements from Mr. Gibson and Der Gebirgsjager and I had to start thinking in different directions.
Some of you suggested a slower powder. That made no logical sense to me based on what I know, which isn't much. The most outstanding piece of info being that, according to quickload, not all of this powder is burnt before the boolit leaves the barrel. Meaning pressure is maintained throughout the boolit's travel until exit. Using a slower powder would only mean that even more powder would be contributing to an already wasteful and pointless fireball and adding absolutely nothing to internal ballistics other than a slower build in pressure (not sure how that might help). I'm by no means sure that I'm right about this part and welcome any argument to the contrary, for sake of knowledge, regardless of relevance. Merely trying to help you follow my train of thought.
Here's the problem with my train...(Don't worry. It doesn't go off the rails. But still probably best not to follow too close, as it does get a little shaky.) I have tried slower powders. Or, rather, A slower powder. The only other load I ran through this thing is a 95gn fmj hp (from everglades, so no data to be found) over unique. Never got around to titegroup in this particular piece.
The load I worked up and use is middle of the road, per Speer manual. Exactly middle of the road. 4gn unique under a 95gn pill. (range is 3.8-4.2) So much for my logic, huh?
So, what the heck was I missing? Pressure. Pressure in my original unique load. See, I worked that load up early on and was unaware, at the time, the effect that seating depth had on pressure. I knew it had some effect, but not how much. I just smashed the pill in until it fit nice in the pistol. And apparently got lucky.
4.0gn unique is minimum for reliable function. Turns out (after some measuring and math) that load is nearly equal in pressure to 2.15gn of RD under this 125gn boolit at my OAL. (This, according to QL.) Which makes sense, when you consider the differnce in function between 2.1 and 2.2 grains of RD under the 125gn pill.
The hottest load I tested while working that up was 4.4gn unique. It shot fine. But, I didn't think the spousal unit would appreciate the level of recoil. So I backed it down. According to QL, that's on par with 2.4gn RD in this new load, pressure wise.
I'm thinking I should feel safe with a 2.2gn RD load with this boolit and OAL. (Which, I think, is what Mr. Gibson said I should do. More or less.) Thoughts?