.1 grain of powder make a difference?

YamaLink · 04-01-2010, 13:36

Setup: G34. Totally stock except for Warren sights and polish job on internals.

WSF at 4.8 and 4.9 and 5.0 batches
Federal primer
OAL is 1.130 give or take
MG 124 fmj

So I'm sampling a bunch of the above and the 4.9 and 4.8 seem the same. Casings anywhere from 1 to 3 feet away. The 5.0 is about 2 to 5 feet. One FTE with the 4.9 (one-handed drills), accuracy is my typical newbie G34 self which means low/left due to poor trigger control or pretty darn spot on which means I actually took the time to get a sight picture and work that nice trigger at distances up to 15 yards.

From a competition shooting perspective is it going to matter at any distance having a 4.8 or 4.9 or 5.0 (I stopped at 5.0 because above that I could tell a diff in recoil and time back on target).

Question: Would you go with the highest powder charge for distances up to 25 yards? My sights are set for 6 o'clock hold if that matters. Or would you go with the lowest recoiling?

I've only shot up to 15 yards due to bad weather. Until I can march off 25 yards and practice targets....thought I'd ask here.

CTSixshot · 04-01-2010, 14:10

My older "Winchester Reloader's Manual" lists 4.7 to 5.3 for WSF with the 124g FMJ. It looks as if you should meet Power Factor of 125 for any of these loads, if that is even a necessity. You'll have to see if the 1 or 2 tenths grain makes any difference in point of impact and decide accordingly. As long as they all function and shoot well for you, I won't notice a tenth grain from my house.

PCJim · 04-01-2010, 14:15

You're asking two questions if I read your post correctly...

Quote:

Originally Posted by YamaLink

From a competition shooting perspective is it going to matter at any distance having a 4.8 or 4.9 or 5.0 (I stopped at 5.0 because above that I could tell a diff in recoil and time back on target).

I would have to say, no. A difference of 0.1gr of powder at those charges will not be noticable up to 25 yards if shooting without a bench rest.

Quote:

Originally Posted by YamaLink

Question: Would you go with the highest powder charge for distances up to 25 yards? My sights are set for 6 o'clock hold if that matters. Or would you go with the lowest recoiling?

I would use the charge that feels most comfortable and allows your quickest sight reacquisition. Again, unless you are benchrest shooting or measuring velocities over a chronograph, you probably will not notice any difference on the target.

Now, if we were discussing a spread of 0.5gr powder charge from min to max, I would expect you to be able to tell a difference. And at 25 yards, it could probably be discernable on paper.

IndyGunFreak · 04-01-2010, 14:20

Well, eventually .1gr is gonna make a difference between blowing up and not blowing up...

In your application though, it probably doesn't make that much of a difference. Just follow PCJim's advice for picking out what you want to use, and have fun.

YamaLink · 04-01-2010, 14:22

Thank you all.

MoNsTeR · 04-01-2010, 15:04

If those are traditional round nose FMJs I would bump the OAL to 1.169". But to answer your question, a tenth of a grain is not going to make much difference with a medium speed powder like WSF.

YamaLink · 04-01-2010, 15:21

They are https://secure3.mooseweb.com/montana...mm-FMJ-124.jpg

34 OAL range seems to be all over even up to 1.16. Most seem to be at 1.13-ish depending on bullet specs.

I just built some 4.8 rounds at 1.15 and see will see how things go. Probably should take some 5.0 at 1.15.

Why would you go 1.169, the max?

Quote:

Originally Posted by MoNsTeR

If those are traditional round nose FMJs I would bump the OAL to 1.169". But to answer your question, a tenth of a grain is not going to make much difference with a medium speed powder like WSF.

fredj338 · 04-01-2010, 17:03

I don't think 0.1gr diff in charge wt is noticeable on a target @ 25yds. it may shoot tighter groups or not, but should have no affect on POI.

KB2MBC · 04-01-2010, 17:17

Gotta remember there is numeric rounding on a digital scale.
On a digital scale that displays down to tenths, 4.9 grains can actually be a charge weighing in between 4.851 and 4.949, or simply +/- 0.05 grains.

fredj338 · 04-01-2010, 17:27

Quote:

Originally Posted by KB2MBC

Gotta remember there is numeric rounding on a digital scale.
On a digital scale that displays down to tenths, 4.9 grains can actually be a charge weighing in between 4.851 and 4.949, or simply +/- 0.05 grains.

Which would also mean nothing, exspecially w/ medium to slow burn rate powders.

BBJones · 04-01-2010, 17:53

Quote:

Originally Posted by YamaLink

They are https://secure3.mooseweb.com/montana...mm-FMJ-124.jpg

34 OAL range seems to be all over even up to 1.16. Most seem to be at 1.13-ish depending on bullet specs.

I just built some 4.8 rounds at 1.15 and see will see how things go. Probably should take some 5.0 at 1.15.

Why would you go 1.169, the max?

For my G17 I load to 1.14 OAL for both 115FMJ and 124FMJ. No real good reason for it, but has worked well and I don't see a reason to change it.

YamaLink · 04-01-2010, 18:29

Wow, I owe a big thanks!

Went back with 1.15 oal and 4.8 and 5.0 WSF; Montana Gold 124 fmj.

The 1.15 was insanely more accurate, easier shooting, faster back on target, less recoil (not that the recoil of a 1.13/4.8 WSF is anything). Each round passed cleanly and ejected about 2 to 3 feet.

This morning was the 1.130 at 4.8 WSF. Took a mag's worth of that along this evening. The OAL difference of going to 1.15 made my shooting seem almost effortless.

KB2MBC · 04-01-2010, 18:59

Quote:

Originally Posted by fredj338

Which would also mean nothing, exspecially w/ medium to slow burn rate powders.

Umm, yeah. Pretty much.

shotgunred · 04-01-2010, 20:10

Quote:

Originally Posted by YamaLink

Wow, I owe a big thanks!

Went back with 1.15 oal and 4.8 and 5.0 WSF; Montana Gold 124 fmj.

The 1.15 was insanely more accurate, easier shooting, faster back on target, less recoil (not that the recoil of a 1.13/4.8 WSF is anything). Each round passed cleanly and ejected about 2 to 3 feet.

This morning was the 1.130 at 4.8 WSF. Took a mag's worth of that along this evening. The OAL difference of going to 1.15 made my shooting seem almost effortless.

My current IDPA load is 4.7 WSF 1.1 OAL Rainier 125 FMJ.
It makes power factor with a G17 and is plenty accurate.

MoNsTeR · 04-02-2010, 09:31

Quote:

Originally Posted by YamaLink

Why would you go 1.169, the max?

Because it is the max (more case capacity = safer), and also because that is factory length and the length that 9mm guns have been built around since the Luger.

DoctaGlockta · 04-02-2010, 17:17

Yes .1 grains does make a difference over......

One million loads

cyberiad · 04-03-2010, 07:52

Quote:

Originally Posted by MoNsTeR

Because it is the max (more case capacity = safer), and also because that is factory length and the length that 9mm guns have been built around since the Luger.

I don't have any 9mm loaded that long but at 1.169 they may not fit in a Glock magazine.

MoNsTeR · 04-03-2010, 10:05

Quote:

Originally Posted by cyberiad

I don't have any 9mm loaded that long but at 1.169 they may not fit in a Glock magazine.

Measure a round of Winchester factory 115gr FMJ, it will measure 1.170". If factory ammo didn't fit in Glock magazines I'd think we'd be hearing about it.

cyberiad · 04-03-2010, 10:19

Quote:

Originally Posted by MoNsTeR

Measure a round of Winchester factory 115gr FMJ, it will measure 1.170". If factory ammo didn't fit in Glock magazines I'd think we'd be hearing about it.

The last measurements I have are from some time ago:

Fed AE 147gr TC 1.061
Fed AE 115gr FMJ 1.151
Fed AE 124gr FMJ 1.151
Blazer Aluminum 115gr 1.115

My notes are not complete but I think the last "white box" I had was around 1.146

Maybe it's all changed now.

CitizenOfDreams · 04-11-2010, 02:51

Here are some factory 9mm 115gr FMJ ammo measurements (10 rounds average)...

Federal American Eagle 29.29mm/1.153"
Precision Delta 29.37mm/1.156"
Golden Bear 29.43mm/1.159"
Wolf 29.50mm/1.161"
Winchester 29.50mm/1.161"
Sellier & Bellot 29.52mm/1.162"

dudel · 04-11-2010, 05:02

Only a chronograph will tell you. As Indy said at some point, yes, it will make a difference between a safe load and an unsafe load. If .1 less works for you why not do it and save powder. A 1/10th here, and a 1/10 there, eventually you've save a pound of powder. Of course, you have to wonder just how accurate your powder dump is.

MarkTX · 04-11-2010, 05:49

Quote:

Originally Posted by dudel

Only a chronograph will tell you...

+++1

When I read G34 and "competition" I think IDPA.

With that in mind you have to make power factor and the only way to be sure of it is with a chronograph. With my chosen load a difference in X.8 X.9 rarely is noticable by me the shooter with recoil feeling the same and POI being identical. But that change has always been noticable to the chronograph with all else being equal.

thorn137 · 04-11-2010, 10:06

Quote:

Originally Posted by MoNsTeR

Measure a round of Winchester factory 115gr FMJ, it will measure 1.170". If factory ammo didn't fit in Glock magazines I'd think we'd be hearing about it.

Yep. I've got a WWB 9mm round that measures 1.169" that I keep on the shelf for die setup.

thorn

Knight Diver · 04-11-2010, 13:33

Quote:

Originally Posted by MoNsTeR

Because it is the max (more case capacity = safer), and also because that is factory length and the length that 9mm guns have been built around since the Luger.

Can someone explain to me what the "more case capacity = safer" part means? Thanks.

fredj338 · 04-11-2010, 13:45

Quote:

Originally Posted by MoNsTeR

Measure a round of Winchester factory 115gr FMJ, it will measure 1.170". If factory ammo didn't fit in Glock magazines I'd think we'd be hearing about it.

It depends on the bullet shape & wt. At 1.169"OAL, there isn't much 115grRNFMJ left in the case. The OAL is "safer" if you have no chronograph to help you adjust your powder charge wt. You can seat a 124gr bullet as short as 1.050" & be "safe" as long as you adjust the powder charge down to achieve the same vel as longer OAL w/ higher powder charges.