Need to up the velocity - more powder or shorter OAL?

[JAFO]

I just got some 147 gr coated lead flat point bullets from Precision. I know Titegroup isn't the best powder, but I've got like 10lbs of it, so I wanted to give it a shot. The loads I tested today were based on Lyman's loading manual. It lists a 147gr lead bullet backed by 2.5gr of Titegroup at 1.058" OAL making 870fps out of a 4" test barrel. They list the max load as 2.8gr at 943fps.

Well, I loaded 20 rounds each of 147gr Precisions over 2.5gr and 2.7gr of Titegroup at 1.13" OAL. Out of my 5"-barreled X5, they gave me the following:

9mm 147gr LFP bullet (average weight of 10 randomly chosen bullets = 148.1gr)

Federal #100 small pistol primers

Mixed brass

OAL = 1.13"

Cloudy with a little drizzle, 87 deg F

2.5gr Titegroup

Hi: 793

Lo: 740

Av: 775

SD: 14

PF: 114

2.7gr Titegroup

Hi: 895

Lo: 752

Av: 804

SD: 28

PF: 119

I'm guessing that the majority of the difference between my loads and the Lyman data is OAL. The powder charge and bullet weights are the same, and my barrel is 1" longer, which I would think should give me more velocity.

I'd like to get to 130-135 PF, but I'm not sure which will be the best way to increase velocity - increasing the powder charge or shortening the OAL. I planned to experiment with both.

I didn't see any primer flattening at 2.7 gr, so I was thinking of leaving the OAL at 1.13" and increasing the charge weight to 2.9gr. Maybe more if I don't see any high pressure signs. But I also worry that too much hot, fast powder could start leading up the barrel.

I was also going to test 2.5gr again, but make up some batches at 1.12", 1.11", and 1.10" OAL. The profile of the Precision just contacts the rifling at 1.14", which is why I went with 1.13" to start. I suppose if I get close to PF with one of the shorter OALs, then I could try bumping the powder a few tenths of a grain to see if the SD might improve.

Any ideas on which approach would yield better results?

[al503]

The lead bullet used in the Lyman manual is probably longer than your Precision bullet because the Precision doesn't have a lube ring and it probably has a round nose instead of a flat point. All other things being equal, the longer the bullet (not the loaded round), the higher the velocity.

I'd up the powder charge and load as long as your mags and freebore allow. That keeps the initial pressure spike down to a minimum.

At 1.13", I wouldn't be worried with the charge needed to get you around 130+ PF. You'll probably be around 3.2 to 3.3 grains.

[Sarge]

Those charges are really low. I think you will end up in the mid 3 grain range before you even get close. I predict 3.6

[Steve RA]

I'd suggest finding the OAL that is most accurate for your gun and then vary the charge weight until you reach your desired velocity/PF.

[vluc]

Not sure what the difference in a TG powder charge would be between a lead 147 and a zero 147, and I'm at 3.4/3.5 for a PF of 138 through a Glock 34. OAL is 1.126 single, 1.131 full shell plate.

[JAFO]

OAL is 1.126 single, 1.131 full shell plate.

That's interesting. I've found that my OALs are a bit shorter with a full shell plate.

[JAFO]

Those charges are really low. I think you will end up in the mid 3 grain range before you even get close. I predict 3.6

Judging from what others are saying they are using, I'm wondering how the Lyman data is getting the velocities they have listed. I'm using the 49th Ed.

I'll focus on upping the charge weight.

Edited September 20, 2013 by JAFO

[JAFO]

The lead bullet used in the Lyman manual is probably longer than your Precision bullet because the Precision doesn't have a lube ring and it probably has a round nose instead of a flat point. All other things being equal, the longer the bullet (not the loaded round), the higher the velocity.

I haven't compared the length, but both the Lyman and the Precision have a flat point.

[fltbed]

OAL is about functioning. (yes, it effects velocity and accuracy to a small degree)

If you want more velocity, increase the powder charge or switch to a different powder.

I shot precision’s years ago until they came out with the current swaged design.

The current truncated flat point design required a rather short 1.095 OAL in order to fit in my chambers. With TG and WST, I was getting what I felt were excessive pressure signs before I was making 130 PF. (was ok with WSF) That and the horrible bore fouling I was getting in my XD9, made me switch to Bear Creek’s.

Jeff

[Rokihsa]

I load 147 bayou at 3.1 tightgroup, 1.135 OAL mixed brass with a power factor of 130 out of a stock glock 34. Clean shooting and almost no recoil.

We did test it up to 3.6 grains at .2 grain intervals, and found it jumped in a hurry to about 147 PF with some snap and backed back off. 3.1/.2 seemed like the sweet spot for my glock.

Edited September 24, 2013 by Rokihsa

[02doooce]

FWIW

I usually find an OAL that works for the firearm I am using and set it to that.

Then I modify the powder drop based on chrono results on the specific gun (different barrel lengths give you different results for PF).

I also try to load to 130-135 PF (for minor).

Note:

In terms of making PF you need to figure out if your powder is affected by temp (for example WST burns slower when it's hot outside giving you a lower PF)

[rowdyb]

147 grain plated bullets, 3.2 grains titegroup, federal spp, mixed range brass, 1.140 overall length. i very consistently get a pf of 129 or 130 out of this combination. it is the load i use for my practice ammo and also for matches (where i case gauge each and every round along with the other inspections.)

i'm loading on a dillon 1050

[CocoBolo]

If you go to precisions web site on the FAQ it plainly says not to use TiteGroup. There is a reason for this, it melts the assend of the bullet off before it can get out the barrel, leaving a trail like a sea gull flew thru it. What you save on the powder you will use in flitz cleaning the barrel. That said Precision and Bayou bullets take about the same charge, @3.0 for your application. Both Precision and Bayou bullets are excellent. Also look at that FAQ on the precision site, and if you are using the Lee FCD, don't, it undersizes the bullet and causes it to wobble down the barrel leaving a trail of moly and lead, for you to clean up.

OAL and charge while related are apples and peaches, you vary the OAL based on how it fits and works in your gun, like the man said find the size that is accurate, well that comes after you get it to fit and feed.

Loading Manuels are a good guide, but unless they have the exact same bullet you are loading you have to make intelligent adjustments, which you did by starting low, now you just need to work it up to where you want to be, and in that realm my rule of big toe is to make it as long as will work in the gun, no shorter, as longer is always safer when it comes to pressure. I load 9 major I live dangerous every time I pull the trigger, my loads are way off the charts.

WST, N320, W231, will work without the melt down of TiteGroup, and produce better results.

[freakshow10mm]

Not sure it will help any at this point, but when I'm working up a load, first and foremost I find my OAL. My end point is the longest OAL that will feed from the magazine and chamber in the weapon by hand-cycling the slide. Then I start at the start charge and work up. The first loads might not cycle the weapon or have some soot on them, but when the pressure gets up there and things get moving, that's when I start judging the results and taking notes. I run the charge all the way to max or pressure sign rears it's ugly head. Then I go back to the most accurate loads and chrono a bunch of them to get the most accurate load that will make PF and be the easiest to shoot.

[JAFO]

Sorry I haven't updated this thread. I went back out and tested 20 rounds each at 2.9 gr, 3.1 gr, and 3.3 gr with the same OAL. I don't have the chrono data with me right now, but I'll try to put it up later. I saw no high pressure signs with any of the loads. The 2.9 gr load got me to 126 PF. The 3.1 gr and 3.3 gr were both over 130 PF with good SD (<10) on both, but the smoke was noticeably greater at 3.3gr.

I ended up trying a 3.2 gr load that ran fine in my last match (~140 rounds). The 3.2 gr is still a bit smokier than I remember the 3.1 gr load being. It could just be my imagination, and 0.1gr may not make any difference, but I'll load 3.1 gr next time.

I haven't tried cleaning the gun yet. It certainly looks filthy, but it looked dirty after 60 chrono rounds, too. That time, it cleaned out with Gunslick foaming bore cleaner and ~10 passes with a bronze brush, so I'll have to see how hard it is to clean after 140 rounds. Precision's website states that the bullet coating contributes to bore fouling, but it's a lot easier to clean than lead.

I actually did e-mail Precision about using Titegroup, since it was specifically not recommended on their site. I got an e-mail back from Dave Long saying it was fine to give it a try. He has a lot of people reporting that they get too much smoke and fouling, but he also has some customers that have no problems with it.

[JAFO]

Here's the chrono data for the last set of test loads out of my X5 (PFs calculated using average velocity & 148gr bullet weight):

9mm 147 gr LFP bullet (average weight 148.1 gr)

Federal #100 small pistol primers

Mixed brass

OAL = 1.13"

20-shot test groups

2.9 gr Titegroup

Hi: 880

Lo: 836

Av: 857

SD: 10

PF: 126

3.1 gr Titegroup

Hi: 917

Lo: 887

Av: 903

Sd: 6

PF: 133

3.3 gr Titegroup

Hi: 946

Lo: 927

Av: 936

Sd: 4

PF: 138

[lcs]

Read CocoBolo's post. You will get leading in the barrel. Titegroup has nitro and burns hot! Titegroup is great for complete metal jacket.

You got more smoke because you are burning off the coating and melting the lead.