FTF with N330 under 125gr HAP in G34

[cwsanfor]

I am developing a load using Vihtavuori N330 under 125gr Hornaday HAP bullets In new Starline brass. I used an OAL of 1.1 after finding that 1.125 touched the rifling in a Glock G19, G26, and G34. That OAL passes an L. E. Wilson case gauge, and will both drop out of and spin in all three barrels.

I loaded 4.1, 4.3, and 4.5 gr N330. All three loads chambered and fired well in the G19 and G26, but I got repeated FTF in the G34 except with the 4.5gr load. QuickLoad predicts 31,139 psi and 1,133 fps for the 4.3gr load, and 34,853 psi and 1,172 for the 4.5gr load.

I don't mind loading to +P pressures, but thought it odd that I apparently anything below the SAAMI maximum pressure with these components won't cycle the G34, or presumably a G17. It caused me to wonder about the OAL, but I know several people loading HAP to 1.10, and the lack of FTF in the two shorter barrels suggest that the heavier G34 slide just needs more power.

It just seemed odd that since N330 at 4.7gr yields (according to QuickLoad) 39,162 psi and 8.9% compression, for a load that will reliably cycle but not blow up the G34, I am limited to 4.5 and 4.6gr in a powder that was "designed for 9mm". I guess that since N330's range between starting and maximum load is usually only about 0.6gr (VV and Hornady data), this is just the nature of the beast.

Anybody load this combination, or have any related experience, that would care to comment? Thanks.

 

[MtnCreek]

Failure to Fire or Failure to Eject?

Does your G34 have all original springs? With the other two handguns, where does the brass drop when fired?

 

[cwsanfor]

I currently have all stock springs, so as to comply with GSSF rules. The G34 does not eject nearly as far as the G19 or the G26: indeed with 115gr Federal ammo it ejects just a foot or so to my right. The G34 tosses brass a bit further with Winchester NATO cartridges, so I guess the G34 slide is just heavier than I expected. I realize I could use a lighter recoil spring, but I like to practice with what I shoot at GSSF.

 

[cwsanfor]

By FTF, I meant "Failure to Feed". The spent brass ejects, but the round being loaded sort of sticks on the feed ramp. Hornady states a COL of 1.060 for the 125gr HAP, so I loaded a 1.1 COL, the longest COL I could (without touching the rifling) trying to minimize feed issues.

 

[MtnCreek]

When the firearm attempts to cycle, does the slide move back far enough to properly engage the round in the magazine? Is the rd that fails to feed abruptly lodged into the feedramp?

It sounds like you’ll have to reduce the COL to allow proper feeding. Have you fired these through a chronograph?

 

[cwsanfor]

When the FTF occurs, the slide is about half way back to being in battery, and the round that was attempting to load is angled up at the base of the feed ramp.

My guess is that the lower powered cartridges did not push the slide all the way back, or pushed it more slowly. I've polished the feed ramp, and have not had this issue in this gun even with mild rounds like Federal 115gr. I don't think I was limp-wristing, because the hotter rounds all load 100%.

I will chrono these this weekend, I was just doing preliminary test to see what would cycle.

I was concerned that a shorter COL would <impair> feeding, and thinking that the longer COL would <help> feeding, but perhaps I should load some closer to 1.060 (Hornady's recommendation, a minimum value) and see if that helps. I know of at least one guy loading these at 1.1 COL in a Glock, but perhaps my slide is tighter than his, this G34 being fairly new.

Thanks for the quick reply.

 

[snuffy]

That's interesting because I just got 500 of the 125 HAP bullets for my CZ-75B CWC. I haven't loaded any yet, wouldn't be using vit powder, but the OAL I would be wondering about.

I'd bet the shorter OAL would feed better. The only way to tell is to try it. OAL for the 124 XTP is 1.060, since the HAP is simply the XTP without the internal skiving to make it expand, the point shape is the same.

I just got the new Hornady 8th edition loading book. The HAP bullet is not even listed for 9mm or for the 357 sig which is where I use it the most.

In fact, Hornady lists 4 bullets for 124 grain,BUT three of them are listed as discontinued. You have to wonder what's going on at Hornady!?

 

[cwsanfor]

I believe I'll load 50 cartridges from 1.07-1.10 COL, vary the powder to keep the pressure and velocity about constant, and chrono that batch in all three guns, and I should be able to tease out whether it is the power factor or OAL that is causing the misfeeds. So I'll load:

COL, gr N330, psi, velocity
1.07, 4.1, 1124, 32972
1.08, 4.2, 1134, 32980
1.09, 4.3, 1143, 33015
1.1, 4.4, 1153, 33073

 

[Steve C]

If your slide isn't coming back far enough to feed ammo from the magazine properly or doesn't have enough forward force to feed the next round there could be a several different reasons.

Springs, either the recoil springs too light or the magazine spring is too heavy, esp true if the failure is consistently the first and/or second round out of a full magazine.

Shooter not holding the pistol tight enough, movement reducing the slide speed and force enough to prevent proper functioning.

Shooter placing finger or thumb against the slide and the drag is reducing the slide speed and force enough to prevent proper functioning.

Gun is dirty so the slide speed is slowed too much.

Round is hanging up on the magazine or feed ramp, could be the case mouth doesn't have enough crimp to remove all the flaring, could be the magazine.

If the rounds will feed and eject when the slide is operated by hand then there is something happening when shooting that changes what happens when hand operated.

 

[MtnCreek]

If the rounds will feed and eject when the slide is operated by hand then there is something happening when shooting that changes what happens when hand operated.

Good Point.

 

[1SOW]

I used an OAL of 1.1 after finding that 1.125 touched the rifling in a Glock G19, G26, and G34. That OAL passes an L. E. Wilson case gauge, and will both drop out of and spin in all three barrels

With your push test, a 1.1" oal should run fine.
If your case ejections (manually slingshot slide) are short, it's likely the recoil spring is too heavy for your load.

 

[cwsanfor]

Thanks for the replies.

My chronographing this weekend was rained out, but I went to the range yesterday and shot 50 Win NATO 124gr and 50 Federal 115gr through the G34, G19, and G26 with zero problems. That seems to vindicate the guns. I'll return to the reloads this weekend. I loaded a ladder with the same predicted pressure but various OAL, and a ladder with the same OAL but varying powder charges.

I'm thinking the FTF issue may have been related to some combination of:

1) Lower power factors, since only the softer rounds gave a problem,
2) I used Imperial Sizing Wax (which I usually do not) on those rounds because I was using a new set of dies, and I did not tumble or wipe the finished rounds, so they may have been a bit sticky,
3) Possibly a OAL issue,
4) I had just installed Match Grade Slide Locks in all guns and had run fewer than the suggested 200 rounds through them (this seems like an unlikely cause).

I usually try to only change one thing at a time, and here I changed four (new dies, new load recipe, using sizing wax, and changing slide locks). We'll see. My current batch of reloads was tumbled after seating, each one chambered in a Glock barrel, tested in a Wilson case gauge, and manually cycled through a Glock, so I bet they all shoot fine.

 

[MtnCreek]

Let us know how it turns out. Also, I'd like to know how those HAP's shoot.

 

[murf]

have you tried a different magazine?

murf

 

[cwsanfor]

I finally got to chrono these rounds this weekend. I shot

1) 10 each in the G34, G19, and G26 with a fixed 1.1 COL, with loads of 4.1, 4.3, and 4.5 gr VihtaVuori N330,
2) 10 each with 1.1 COL/ 4.5 gr, 1.08 COL/4.3 gr, and 1.065 COL/ 4.1 gr (for a roughly constant 35,000 psi predicted),
3) 10 each Hornady Steel Match 124 gr (which I'm trying to duplicate)
4) 10 each Winchester NATO and Federal 115 gr for a comparison and chrono verification, since I know their velocities).

All rounds were delubed this time, and I had previously fired 100 each of the NATO and Federals through each gun with no malfunctions.

I got two FTE and two FTF in the G34 with 4.1 gr N330 at 1.1 COL, and one FTE in the G26 with 4.1 gr at 1.1 COL. These two guns are newer than the G19, and probably a bit tighter. If the G19 were new, I suspect it would not have reliably run the lowest charge.

What I think happened is this: QuickLoad underpredicts the velocity from N330 under HAP much more than with 3N37 under Delta Precision 124 gr FMJ RN. Rather than the predicted 1,094 fps from the G34, a 4.1 gr 1.1 COL measured only 862 fps, a 232 fps difference, and only 108 Power Factor. I think this is just not enough to cycle the action in a fairly new G34. The COL does not seem to be a factor, and probably not the lube.

So this weekend I'll chrono 1.1 or 1.09 COL HAP over 4.4/4.5/4.6 gr N330 and see what that does. QL predicts the hottest of those at 39,000 psi, but I'm pretty sure it is high by at least 10%, so I'll work up to that load looking for overpressure signs.

In the unlikely event that anyone wants to see the data from this past weekend, it's at https://spreadsheets.google.com/spr...V3hlTjZTWWlEc3ZDWEE&hl=en_US&authkey=CPuW35sF .

Thanks for the feedback.

 

[Galil5.56]

Cwsanfor,

Does QL spec 125 grain HAP bullets @ .356" diameter, as spec'd from the maker?

 

[cwsanfor]

Yes, that bullet is in the current QL database, as is the 121 gr HAP at .356.

 

[PO2Hammer]

I use the 125 HAP quite a bit, it's the most accurate affordable bullet I've found for 9mm and .38 Super.
I use a OAL of 1.090".
Both the G-34 and 17L take a little extra power to cycle compared to the G-19. My G-19 will cycle the HAP at about 950 fps, the 17L needed 1,050 fps.

FWIW, the HAP measures .3566" with my micrometer. I've used it in a lot of guns including Glocks, S&W, HK's, a Marlin Carbine.

Saturday I loaded the 125 HAP and the 124 XTP (.3555") with the same settings on my dies and powder measure using Universal. OAL, velocity and extreme spread were identical with both bullets.

I think you're right on about the power level being lower than predicted.

How do you like N330?

 

[cwsanfor]

I like the N330, it's clean and shoots pretty soft. I've got 3N37, 3N38, PowerPistol and some N320 for hotrodding, but I'm trying to make a single round that I can practice and compete with, affordably, in all three guns, and the N330 seems like a good candidate, as does the HAP. Can't push the N330 too hard, though, the pressure curve accelerates fairly steeply with hotter loads. I suspect I'll end up with a 1.09 COL over 4.6 or 4.5 gr N330.

Do you use QuickLoad, or have any idea why it seems to so badly overestimate velocity and pressure with this bullet/powder combination?

 

[PO2Hammer]

No, but in a tiny case like 9mm, changes in bullet length/seating depth will have a greater effect on velocity and pressure than they would in say a .357 magnum.

I suspect that pressure and velocity are really hard to predict in 9mm, even with a computer program. Quickload is probably programmed to err on the side of caution.

I was supposed to get a 4lb jug of N330 from my distributer, but that fell through. I'm happy with SR 7625 in 9mm. Also a single base powder and very clean burning, meters well too.