9mm chrono ?

[ultrablue]

Got my new Dillon press up and running. Great machine. Even the kids say it looks like a little factory.

Loaded 124gr bullets with 4.0 grains of Bullseye. XDM 4.5 ran great with this load and the felt recoil was lighter than factory 124gr ammo.

My question, Do I need to chrono this?

How important is the chrono measurement?

I am shooting USPSA as production, minor and yet to be classified.

[Jman]

Got my new Dillon press up and running. Great machine. Even the kids say it looks like a little factory.

Loaded 124gr bullets with 4.0 grains of Bullseye. XDM 4.5 ran great with this load and the felt recoil was lighter than factory 124gr ammo.

My question, Do I need to chrono this? Yes...have it "chrono'd" before the next match. What does your manual tell you about expected velocity for your load?

How important is the chrono measurement? Very. Review your rule book.

I am shooting USPSA as production, minor and yet to be classified. Well....get to it.

[UW Mitch]

It's always sad to see a new shooter chrono sub-minor and not get to be scored at a match. And the matches with chrono are usually the "bigger" ones, so its' doubly sucky. Find out of any of the folks in your club have a chrono they'd set-up to let you use - or piggy back on a friends chrono session. I did that for many years - I finally bought my own.

~Mitch

[Loop51]

In case you arent familiar, you need to reach a power factor of 125 to be "minor"...Probably want to shoot for something like 132-134 just to be safe.

(Bullet weight x velocity) / 1000 = power factor

[ultrablue]

Thanks for the answers folks.

I knew the minimum per USPSA was 125 for minor power.

I don't have a chrono so that is part of the dilema.

IF just going to the range and everything cycles I guess was really the question.

From a technical standpoint and for match rules I understand the need for the chrono data.

As a newbie I was excited that everything worked.

I haven't found the exact load I used in any manuals. It was from reading and asking questions to start with that initial recipe.

Next question;

If I use 124 grain bullets for matches should I stay with that for general paper or go to 115 grain?

[OpenDot]

if you're going to reload get a chrony off ebay for $100

[RePete]

Stick to one bullet weight for practice and matches.

If you were in my 'hood, I'd say come on down and chrono your stuff through your gun.

[Loop51]

I am still pretty new to all this myself but I will give you my thoughts on bullet weight...

I initially shot only 115gn...Found them to be fairly inaccurate and had trouble knocking down long distance poppers.

I then moved to 147gn. Better accuracy, more knock down (IMO) and easily makes power factor with a soft shooting load. However, I found the gun to run "slow"...Like it took awhile for the sights to settle back down. Recoil was almost non existent but the gun was sluggish. Tried a few different powders, really didnt help much...

Finally, I switched to 124gn with N320 and couldnt be happier. Easily knocks down steel, accuracy is superb and the gun is less snappy than the 115 but very quick to return to battery. Sight tracks up and down so its easy to follow which makes for faster follow up shots.

I use the same load for everything, helps me keep the timing down on the gun.

Just my observations, your mileage may vary...

[ultrablue]

I am still pretty new to all this myself but I will give you my thoughts on bullet weight...

I initially shot only 115gn...Found them to be fairly inaccurate and had trouble knocking down long distance poppers.

I then moved to 147gn. Better accuracy, more knock down (IMO) and easily makes power factor with a soft shooting load. However, I found the gun to run "slow"...Like it took awhile for the sights to settle back down. Recoil was almost non existent but the gun was sluggish. Tried a few different powders, really didnt help much...

Finally, I switched to 124gn with N320 and couldnt be happier. Easily knocks down steel, accuracy is superb and the gun is less snappy than the 115 but very quick to return to battery. Sight tracks up and down so its easy to follow which makes for faster follow up shots. How many grains of powder?

I use the same load for everything, helps me keep the timing down on the gun.

Just my observations, your mileage may vary...

What gun are you using?

[ultrablue]

Stick to one bullet weight for practice and matches.

If you were in my 'hood, I'd say come on down and chrono your stuff through your gun.

Thanks for the offer.

I am in Southeast Wisconsin. That might be considered God's Country.

[Loop51]

I am still pretty new to all this myself but I will give you my thoughts on bullet weight...

I initially shot only 115gn...Found them to be fairly inaccurate and had trouble knocking down long distance poppers.

I then moved to 147gn. Better accuracy, more knock down (IMO) and easily makes power factor with a soft shooting load. However, I found the gun to run "slow"...Like it took awhile for the sights to settle back down. Recoil was almost non existent but the gun was sluggish. Tried a few different powders, really didnt help much...

Finally, I switched to 124gn with N320 and couldnt be happier. Easily knocks down steel, accuracy is superb and the gun is less snappy than the 115 but very quick to return to battery. Sight tracks up and down so its easy to follow which makes for faster follow up shots. How many grains of powder?

I use the same load for everything, helps me keep the timing down on the gun.

Just my observations, your mileage may vary...

What gun are you using?

Glock 34 for Production. 4.2gn N320 @ 1.140" Very nice load.

[Sin-ster]

You can easily get the gun to cycle with 124 grain that isn't making PF. Just as an example, 3.8 grains of N320 behind a 124 grain MG JHP works my G17 beautifully, but falls just shy of 125.

I would imagine the same thing applies to your XD. While I can't speak to your particular powder or load, upping the velocity for me didn't show much increase in muzzle flip at all. YMMV.

Now for a mild thread hijack...

What's the most variance one can expect between the chrono you use to test your loads, and the one that'll be used at the Major Match to verify the PF?

Let's assume the exact same weather conditions and such, plus a super stable powder, consistent powder drops and OAL, etc.

[ultrablue]

You can easily get the gun to cycle with 124 grain that isn't making PF. Just as an example, 3.8 grains of N320 behind a 124 grain MG JHP works my G17 beautifully, but falls just shy of 125.

I would imagine the same thing applies to your XD. While I can't speak to your particular powder or load, upping the velocity for me didn't show much increase in muzzle flip at all. YMMV.

Now for a mild thread hijack...

What's the most variance one can expect between the chrono you use to test your loads, and the one that'll be used at the Major Match to verify the PF?

Let's assume the exact same weather conditions and such, plus a super stable powder, consistent powder drops and OAL, etc.

Great theoretical questions. How do you plan for the instances you question?

Going to get a chrono and start tetsing to know where I am at.

[Hi-Power Jack]

My question, Do I need to chrono this?

How important is the chrono measurement?

I am shooting USPSA as production, minor and yet to be classified.

Ultra, if your ammo is PF 150 or so, you are at a disadvantage

due to the extra recoil - so you're hurting your times.

If you PF is below 125, you will not consistently knock down

the steel (especially the poppers). Very embarassing to have

to shoot the same target (and hit it) three or four times to

knock it down (don't ask how I know)

You need to chrono your loads - run 20 of them thru the chrono

so that NONE of the 20 rounds are below 125 PF, and the average

will be around 130 - 135. Then you'll be safe and have fun.

Good luck with it.

Jack

[frankge]

this

http://www.walmart.com/search/search-ng.do?search_query=gun+chronograph&ic=48_0&Find=Find&search_constraint=0

[Sin-ster]

Great theoretical questions. How do you plan for the instances you question?

Going to get a chrono and start tetsing to know where I am at.

Whelp, I know the SD and ES of my loads-- including actual bullet weights (in case they get really specific). Based on that, it's not difficult to give yourself enough of a PF cushion to make Minor every time.

The powder I'm shooting is remarkably stable and consistent, so you can do away with a lot of the concern for condition changes as well-- although it's always good to take those into a account, for safety's sake. I'll also be chronoing a lot before every Major, just to make sure things are still working properly-- and adjust accordingly if something has changed.

The one real variable is the differences in chrono, as I've heard about and seen them (to a much lesser degree) first hand. Even the "best of the best" will vary some from machine to machine, even within the same model. I figure if I can get a general idea of just how much this shift is, I can account for that just like it was part of the SD/ES.

I'd rather not crank up to 133 PF, if 130 (or maybe even lower) will do. Other than a (notably) longer OAL, I'm hugging the hairy edge of the (admittedly limited) Manual Data on the bullet and powder combination I'm using. Making 129.6 average PF on my machine (and never lower than 126) feels very comfortable for me-- but when ~25 FPS drops that PF down a number, it could be problematic if I face a machine that's 55 FPS off of my own.

I seriously doubt the SD/ES of any two decent chronos will be that much-- but I don't know for sure!

[ultrablue]

Folks,

I have a chrono now and will start the process of measuring the loads.

I will update as soon as possible.

Thank you for all of the good help.

[1SOW]

Folks,

I have a chrono now and will start the process of measuring the loads.

I will update as soon as possible.

Thank you for all of the good help.

When you build a new load or change bullets, your going to appreciate the chrono for more than just meeting PF requirements. It'll also help you tweek your loads for accuracy, feel, Wisconson temp sensitivity and powder position effects.

You'll also make new friends at the range.

Edited September 2, 2011 by 1SOW

[ultrablue]

I have a spreadsheet of my collected data. how can I share it for comment? I tried to attach it and it wont let me? Any suggestions? It says that type of file is not allowed.

[TonyT]

Got my new Dillon press up and running. Great machine. Even the kids say it looks like a little factory.

Loaded 124gr bullets with 4.0 grains of Bullseye. XDM 4.5 ran great with this load and the felt recoil was lighter than factory 124gr ammo.

My question, Do I need to chrono this?

How important is the chrono measurement?

I am shooting USPSA as production, minor and yet to be classified.

I chronograph every load. I used Bullseye with the old 124 gr. Star FMJ. my data shows a bit less than 1100 fps for 4.0 gr. Bullseye and cq 1170 for 4.5 gr. Bullseye.