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Discussion Starter #1
Quote:
Originally Posted by Old School
Zero 147gr JHP
3.0gr TiteGroup
OAL: 1.150
Primers: Winchester Small Pistol
Brass: Speer, Winchester

My XD has eaten nearly 20,000 of these gems and they have been flawless. Recoil is poofy and the gun runs great.

OS

I used the same load and specs with Hornady fully encapsulated 147gr and they chronoed it at 123.5. Is the bullet the differrence or maybe the crimp or ???
My XD9 5" was brand new and these were the first rounds fired.
Any comments please.
Also, with light loads, should I use the standard spring or #16lb?

At this point, I know the simple answer is increase the load to 3.1. I'm still new to reloading so I'm trying to learn which variable to look at first.

Thanks for your replies..

Joe
 

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Quote:
Originally Posted by Old School
Zero 147gr JHP
3.0gr TiteGroup
OAL: 1.150
Primers: Winchester Small Pistol
Brass: Speer, Winchester

My XD has eaten nearly 20,000 of these gems and they have been flawless. Recoil is poofy and the gun runs great.

OS

I used the same load and specs with Hornady fully encapsulated 147gr and they chronoed it at 123.5. Is the bullet the differrence or maybe the crimp or ???
My XD9 5" was brand new and these were the first rounds fired.
Any comments please.
Also, with light loads, should I use the standard spring or #16lb?

At this point, I know the simple answer is increase the load to 3.1. I'm still new to reloading so I'm trying to learn which variable to look at first.

Thanks for your replies..

Joe
I'm totally lost here. I followed this in the sticky, and didn't get it. Chronoed it at 123.5? What does that mean?

I'm curious about trying loads like these (I'm going to do some research in some manuals before I do), but I'm at a loss to explain what's going on above.

Can anyone shed some light?
 

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Any variable in a load will change things, even different powder lots, bullets, primers, crimp. ALl of that being said, the same round fired from your XD may chrono at a different speed than in MY XD.

I'm totally lost here. I followed this in the sticky, and didn't get it. Chronoed it at 123.5? What does that mean?
Chronograph is used to determine the speed of a bullet. The 123.5 is the PF which is obtained by multiplying the bullet weight by the bullet speed and dividing it by 1000.
 

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I'm totally lost here. I followed this in the sticky, and didn't get it. Chronoed it at 123.5? What does that mean?

I'm curious about trying loads like these (I'm going to do some research in some manuals before I do), but I'm at a loss to explain what's going on above.

Can anyone shed some light?
In USPSA matches you have to meet certain power factors. Minimum power factor is 125. Power factor is figured by multiplying bullet weight x velocity and dividing it by 1,000.

So a 125 grain bullet at 1,000 fps would make 125 power factor.

If my math is correct his loads actually went 840 fps over the chronograph.

AS Icchy trigger said, anything you change, from the gun to the primer, to the brand of bullet can change your over all velocity. Even the elevation, temperature and humidity can effect your bullet velocity.

It looks like you are running real close to minimum power factor and need to bump it up. Best way is to shoot your loads over a chronograph yourself before a match and know what speed your bullets are going. Make sure you give yourself a little pad with some excess speed.
 

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In USPSA matches you have to meet certain power factors. Minimum power factor is 125. Power factor is figured by multiplying bullet weight x velocity and dividing it by 1,000.

So a 125 grain bullet at 1,000 fps would make 125 power factor.

If my math is correct his loads actually went 840 fps over the chronograph.

AS Icchy trigger said, anything you change, from the gun to the primer, to the brand of bullet can change your over all velocity. Even the elevation, temperature and humidity can effect your bullet velocity.

It looks like you are running real close to minimum power factor and need to bump it up. Best way is to shoot your loads over a chronograph yourself before a match and know what speed your bullets are going. Make sure you give yourself a little pad with some excess speed.
To add, all gUns are diff. too. What makes X vel. in one can be as much as 50fps off in another "identical" pistol. AnotheR reason to chrono your loads, make sure you are at least 25fps faster than min. PF. Std. vel. deviation can be that much.
 

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Since I don't compete (someday, someday), I wasn't aware of this. I've been chronographing my rounds, but hadn't run across power factor.

Interesting concept. Thanks for the replies! Learned something today, so it's been a good day.
 

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Discussion Starter #7
Sorry I skipped the velocity part of the Power Factor equation. Looks like you guys cleared it up. I suppose +.1 or +.2 gr will not make a difference in recoil feel or accuracy.
Now back to the original question. When trying to shoot light loads do you experienced shooters recommend a lighter spring to cycle the weapon.
I'm not sure what's standard on the XD9 Tactical but I've got a #16 to try out.
Any input is appreciated
Thanks again

Joe
 

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If your gun is functioning well I wouldn't worry to much about it. If you are experiencing any problems with the slide going back and the round not ejecting properly than the lighter spring is the way to go. Remember that too light a spring makes the slide hit the stop harder and creates stress on the gun. Sometimes that is a fine balance. Does not appear to be too musch of a problem with XD's. I currently use a XD45 with light loads and the factory spring with no problems.
 

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-snip- When trying to shoot light loads do you experienced shooters recommend a lighter spring to cycle the weapon.
I'm not sure what's standard on the XD9 Tactical but I've got a #16 to try out.
The stock spring for the XD-9 Tact and XD-40 Tact is 18#. The slide of the XD-9 is lighter than the XD-40 so the 9 can run the lighter loads.

Win White Box and CCI Blazer 9mm both chrono around 130pf. Many a USPSA Production shooter uses it rather than reloading. I wouldn't change the spring as 123pf ammo should still cycle the slide and go to slide lock at the last round.

Now the work I had to do to get my XD-40 Tact to run 130pf loads (180gr at 735 fps) was a whole different set of issues.
 

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Since I don't compete (someday, someday), I wasn't aware of this. I've been chronographing my rounds, but hadn't run across power factor.

Interesting concept. Thanks for the replies! Learned something today, so it's been a good day.

The other part about power factor is that they have a "Minor" and "Major" power factor. IIRC minor is 125 major is 165.

With either one center (A zone) hits score the same, but minor receives less points than major as you get further out (B, C, and D zones).

The idea is that a Major caliber gun is heavier recoiling and harder to shoot, but going back to the practical roots of USPSA shooting the Major caliber should be better for self defense. So major scores you more points.

It's part of the triad of practical shooting. Speed, Power, Accuracy. Lose any one of the 3 and you won't be a good practical shooter.
 

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This weekend I chrono'd my second batch of reloads. I used 115gn MG JHP and Hornady 115gn HP-XTP comp bullets for buying their press.
5.8gn Power Pistol, WSP primers w/ COL 1.075
MG: avg speed: 1193.4fps, PF: 137.2
HP-XTP: 1172.3fps, PF: 134.8
using 6.2 gns...
MG: 1230.5fps, PF: 141.5
HP-XTP: 1202 fps, PF: 138.2
The Hornady bullets were more consistent speedwise altho a little slower with a more pronounced hollow point, probably a lot more expansion. The MGs are great for punching paper. I'll sitck with the MGs for the matches and maybe go down to 5.6 gns and hopefully be over the 125 PF.
My XD-9 Tactical has had no misfunctions using my reloads :D
 
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