Low pressure problem?

[Eomfd]

I am new to reloading and started my first 9mm batch the other day. I am loading 115 gr rainer plated RN with new Remington brass, CCI primer, and IMR SR 4756. I followed my load data which stated the starting charge be 4.5 grains. I loaded 20 rounds and each round I fired would not cycle to the next round. Also, my barrel would be extremely dirty only after a few rounds. Here is a picture of my casings after I would manually cycle each round. Any help out advice would be greatly appreciated.

[tangolima]

Didn't see your picture. But can you tell us a bit more details? I suppose the pistol extracted and ejected the spent brass ok, but it failed to feed a new round. So the new round was still in the magazine, and the slide just rode over it? Did you chronograph the load?

-TL

[Eomfd]

The casing didn't even eject. I had to manualy rack the slide back in order to eject the spent case and then release the slide to cycle in a new round. The same problem occured on every round. Also, being new to reloading I do not have any capablities to chronograph anything.

[chiefr]

Never heard of anyone using that powder with 9mm

[Eomfd]

I plan on going to the range today and will post more pictures of the non cycling problem actually in the weapon.

[jwrowland77]

My guess would be that if it's not cycling your pistol, then yes, it doesn't have enough umph to make the slide do it's job.

If this was a start up load, then I would continue going up with the powder charge.

The only other thing I can think of that makes the pistol not cycle correctly, is not having the proper grip on the pistol, aka Limp Wristing.

[mdmtj]

I don't have any load data but it looks and sounds like the charge is too low.

[Unclenick]

Hodgdon's data says 4.5 to start and 5.2 maximum, but I note they are using a 1.10" COL, which is pretty short and may be raising the pressure. Your sooty case mouths are a sure sign pressure isn't building fast enough to expand the brass enough to seal the chamber. No question it's a light load in your gun.

[BigJimP]

I'm wondering if you're not under crimping / or not removing all of the belling you put into the case before you dropped powder and seated the bullet....it looks to me, like you're get a lot of blowby of powder or gas around that bullet ..../ that much scorching on the outside walls of the case is certainly not common...

If you haven't done the final crimp properly ...the rounds might be hanging up in the chamber ...( and the mag potentially as well )....

I would suggest investing in a "case gague" to check the finished rounds before you go to the range and fire them.

[Eomfd]

Thanks everyone for the advice! I went to the range and shot 5 rounds with 5.0 grains. Same problem but finally did get the gun to cycle, but only once. I do have a case gauge and measured all 5. All dropped in without any issue. My OAL measures 1.140 +/- .005. I don't know if this matters but my neck diameter after my bullet is seated is .375. Unclenick, would you recommend staying under 5.2 but shorten my OAL?

[tangolima]

Your last picture shows a failure to feed in 3-point-bind manner. So the new load has no problem extracting and ejecting? Are the brass still sooty as before?

I don't have load data for IMR SR 4756, but I have hodgedon HS-6. For 115gr bullet, the powder charge is 5.7gr to 5.9gr for COL = 1.1", and 6.7gr to 7.0gr for COL=1.125". 4756 is burning slightly slower than HS-6. I would expect higher powder charge than HS-6.

-TL

[jimbob86]

Your sooty case mouths are a sure sign pressure isn't building fast enough to expand the brass enough to seal the chamber. No question it's a light load in your gun.

+1

Sooty cases= load too light.

SR4756 in 9mm?

Fairly slow - though Blue Dot is slower yet, and it works pretty well for me, at max charges.

[Nick_C_S]

Your sooty case mouths are a sure sign pressure isn't building fast enough to expand the brass enough to seal the chamber. No question it's a light load in your gun.

^^ +2 ^^

[Nick_C_S]

4756 is in the Blue Dot neighborhood, in terms of speed. So I consider it too slow for the application (9mm/115g) IMO. But you still should be able to tweak the recipe and get it to run in its "sweet spot." You're definitely not there right now. But when you do, it's going to be a fire-breather of a round - tell you that right now. Is that what you were looking for? If not, consider a faster powder.

[jimbob86]

The only time I tried Blue Dot in 9mm (115gr jacketed), the Start Load and Do Not Exceed load were the same: 8 grains, Do Not Reduce.

Pretty loud and flashy out of my 3" barrel .... I decided there were better options.

What did the primers look like? I'd bet they may have backed out a bit....

I'd guess if this powder is "in the BlueDot neighborhood", it will work best at max load.

[Eomfd]

This is a picture of the primer that was filled with 5.0 grains. I will bump up to 5.2 and head to the range tomorrow. I will post those results tomorrow. Wish me luck!

[jimbob86]

..... just looking at the primer, I'll hazard a guess that it was flatter before you fired it.

[Nick_C_S]

Pretty loud and flashy out of my 3" barrel .... I decided there were better options.

^^ Yep! There were better options. ^^

Eomfd: Now would be a good time to take a step back, and ask: You are loading this ammo for what purpose?

Target?
Match Target?
General practice?
High power practice?
High power defense?

Let's start there, and then see where we need to go. . .

And: Do you have any other bullets/powders available to you? I have a hunch we're going to need one or the other

[Eomfd]

I'm using this setup for general shooting. This has been the only powder and bullets I could find at the time. Is sr 4756 used more for a different caliber?

[Nick_C_S]

I have no experience with 4756. But as I understand it, it's a medium-slow burning powder, best suited for larger, magnum-type calibers.

But if it's all you have, then it's all you have.

I think the key here is to not try to make it something it isn't. It is what it is. Okay I'm done with philosophy.

I don't know where your recipe needs to be, but we have thoroughly established that the current condition is very low pressure. In short, you definitely need more powder.

Have you performed a "plunk test" to determine the correct COL (or OAL, or COAL - whatever term you wish to use)? The first step is to set the COL for the bullet/gun combo.

Assuming it's set properly, your next step is to add powder. Given the condition of your brass and primer, you definitely need to add quite a bit more. Conservatively, 10% more (round up to the next 1/10th) would be next step. Although my gut tells me it won't be your last. (This is not to say that you'll be moving in 10% increments - this is just for the first time only. Additional steps will be much smaller.)

As I alluded before, by the time you've created a good clean burning, consistent round, you're going to have a full-power fire-breather. It'll be a good full power practice round - should be fun to shoot. That's what it's going to be - remember, don't try to make the loading something it can't be.

[Valornor]

Just out of curiosity....in this type of situation with a slower powder in a non magnum type application would he be better off using a hotter primer? Assuming that switching powders isn't an option. I'd consider using a small pistol magnum primer....

Just a thought...

[Wreck-n-Crew]

Hodgdon's data says 4.5 to start and 5.2 maximum, but I note they are using a 1.10" COL, which is pretty short and may be raising the pressure. Your sooty case mouths are a sure sign pressure isn't building fast enough to expand the brass enough to seal the chamber. No question it's a light load in your gun.

^^^^+3

Took the words right outa my mouth..

I will say this too, it is best to get a Chronograph for such instances as this. If you would've had one, the slower than normal FPS would tell the tale. Would we have been able to tell the same story had you not used a powder that sooted so much? There are some fast and clean burners out there that would have told you very littl by looking at the casings.

[Nick_C_S]

Just out of curiosity....in this type of situation with a slower powder in a non magnum type application would he be better off using a hotter primer? Assuming that switching powders isn't an option. I'd consider using a small pistol magnum primer.

It's been my experience that the use of a magnum primer can slightly clean up an underloaded recipe.

But the better choice is to bring the load into balance.

[Eomfd]

I haven't been able to sleep much after this issue so I was wondering if sr 4756 is on the slower side of burning rate, would a heavier grain (say 124 or even 147) bullet help by allowing the pressure to build longer in the barrel?

[Nick_C_S]

Absolutely yes. Your 4756 would be very well suited for 147g bullets - especially if your gun is a full-size and has a some barrel length.