Help With Chrony Data

[Capt Roy]

I received a CED M2 for XMAS and finally got it to the range today. It took my XDm 9mm, 4.5...

The M2 was so easy to set and use it amazed me.. Can't wait to go again..

It hooked straight to my computer with Windows 7

I did a couple of strings..

The first was with was with Federal 115g FMJ RN...

After I finished with the chrony I finished the box of 45... No FTE or any other problems..

String 1

_ 1)_1169.0_ -6.2
_ 2)_1179.0_ 3.8
_ 3)_1174.0_ -1.2
_ 4)_1185.0_ 9.8
_ 5)_1169.0_ -6.2

__ High:_1185.0
__ Low:_1169.0
__ E.S.:_ 16.0
__ Ave.:_1175.2
__ S.D.:_ 6.1
__ 95%:_ ±9.6


String 2 was with my reloads..CCI 500 primers, 4.1 Titegroup, MG 124 CMJ, OAL 1.145... I had sever FTE and a couple that did not chamber correctly

String 2

_ 1)_1109.0_ 26.0
_ 2)_1087.0_ 4.0
_ 3)_1095.0_ 12.0
_ 4)_1092.0_ 9.0
_ 5)_1121.0_ 38.0
_ 6)_1103.0_ 20.0
_ 7)_1106.0_ 23.0
_ 8)_1099.0_ 16.0
_ 9)_1105.0_ 22.0
_ 10)_1102.0_ 19.0
_ 11)_1066.0_ -17.0
_ 12)_1088.0_ 5.0
_ 13)_1046.0_ -37.0
_ 14)_1071.0_ -12.0
_ 15)_1071.0_ -12.0
_ 16)_1050.0_ -33.0
_ 17)_1072.0_ -11.0
_ 18)_1047.0_ -36.0
_ 19)_1060.0_ -23.0
_ 20)_1070.0_ -13.0

__ High:_1121.0
__ Low:_1046.0
__ E.S.:_ 75.0
__ Ave.:_1083.0
__ S.D.:_ 21.9
__ 95%:_ ±10.8

Now I need a little help..

I need to make some adjustments before I go again... Should I increase the load to 4.3 (4.4 is max per my data) or try to bring the OAL to say 1.2 to cure the FTE problem???

Also, how do you compute the Power Factor??

Thanks for any input..

God I love this stuff!!

 

[[email protected]]

Fist off congrads on the new equipment. A chrony in the equipment list is as handy as an electronic scale (not necessary but nice to have). Let me warn you though not to get too cought up in chasing the velocity of factory ammo. My first question is what steps did you take to develop the load. I would assume that you worked up the load form the min, but if your like me you started near the middle and went from there. I will try to take a shot at what may be your problem. In my expierence with titegroup and 9mm is that you have plenty of powder and should play with the col. The 1.145 is longer that what i have ever tried and i usually run around 1.130 for a col. My lee manual lists 4.1 to 4.4 with a col of 1.090 for a 124gn jacket bullet. so it is reasonable to believe that you would be ok if you only shortened the col. Since it is stripping a round from the mag further leads me to believe it is the col and you have plenty of powder. Your velocity seems to be in line also. One way to find out what col you need is to load up a dummy round (no powder or primer) and load in you mag and manually cycle the action. If it hangs up try shorter. Just guessing with out knowing your gun, but it will be around 1.120 to 1.130 col. I am cautious to load the 9mm any shorter than what is needed as you can build pressure quickly when shorting the col. I once gave some 40 S&W to a friend. These round work perfect in my glocks 22,27 and a few other glock 22, but they would not feed in his maginum research pistol (believe it was a deseart eagle). After a few hours of tinkering we foung that the chamber was too tight to feed and about .002 difference was needed in the cold

 

[Jim Watson]

Agreed. A 124 gr bullet at 1046+ fps is NOT showing a lack of power.
Consider OAL and other cartridge dimensions.
Try chamber checking your reloads and see that they chamber freely.
If they don't, adjust until they do.

 

[gamestalker]

I'm currently loading the 115 grain Gold Dot with 6.0 grains of Longshot and am getting a very consistent high 1200s with low being 1285 fps. and the high 1297, average was 1291. With a 147 grain XTP velocity was 1050s.
The 115 Gold Dots were average from 10 rounds, the same for the 147 XTPs. I'm not sure what your trying to accomplish but Longshot is a slow burner and will produce some excelent velocity and accuracy is astounding out of my B92F, XDM, and the Taurus 111. The above test data was performed out of the Taurus 111.
Energy in foot pounds for your 1st string high, low, and average 115s you tested is as follows:
The 1185 fps rounds produced: 358.225 Ft. Lbs.
The 1169 fps rounds produced: 346.725 Ft. Lbs.
The average of 1175.2 was: 352.475 Ft. Lbs.

I don't have a calculator in front of me so I had to do the math with paper and pencile which is rather cumbersome. If you really need the Ft. Lbs. for the reloads, let me know and I'll run those numbers for you. Do you have a reloading manual? Most will have the tables in them.
The 115s I loaded with Longshot were producing around 420.0 Ft. Lbs. @ 1297 fps..

 

[1SOW]

PF = bullet weight X velocity / 1000

PF = 124 X 1083 / 1000 = 134.3 (a little higher than needed, but good-to-go)

Check case sizing and crimp, and do the drop-in test on the naked barrel chamber. Might need a slightly lighter recoil spring for proper slide speed when
PF =/< 130

A chrono is definitely needed to put you in the sweet spot.

The MG 124 CMJ will let you load out long. The MG 124 JHP (or FP) will likely need to be down in the 1.11 or even shorter depending on your gun's chamber. The drop in with a 'click' and 'fall' out check will tell you what MAXIMUM length will run in your gun.

My CZ (tight chamber--short distance to the leade/rifling) will run smoothly at your OAL, but I usually use 1.125ish" oal on the 124 MG CMJ bullet in "my" gun. In addition to running smoothly, you want to load so point of aim equals point of impact. Using "just" the chrono and a given power factor may screw that up. The bullet, powder and gun will drive the minimum speed that will give you accuracy. Use a different powder/bullet and it's a whole new ballgame. Tite Group is a fast powder. A slower powder will shoot higher.

Hope this makes sense

 

[Capt Roy]

Thanks for the replies... I do think OAL is the problem... I did a chamber check but I'm going to try it again and adjust down to 1.13 and try a few..

This load was very accurate compared to the federal..


Thanks again