Dillon 650 FPS Consistency

[texasdog]

Hello,

I just started loaded with a new Dillon 650. The powder I am using is Hogden Titegroup and the Primer is (the only onne I could get Remington 2 1/2.

To get my FPS to around 700 I had to go to 4.2 grains. The problem is that the FPS is not consistent.

Sometimes I hit a high of 750. The others, a low of 650. Thats pretty wide!

The chorono I am using is the newest CED.

Any suggestions on how I can get my 45 ACP reloads more consistent?

3x50May09.txt

[h2osport]

Are you sorting your brass? What kind of crimp are you applying? Are you giving the handle a consistent(non jerky) stroke? Make sure your failsafe rod is in place to insure full travel of the powder bar. Are you checking your powder charge on a scale to make sure you are getting consistent charges?

Thats about all I can think of.

Randy

[PhotoRecon]

texasdog:

Assuming they'll still function you might try adjusting the OAL. I went from 1.250" to 1.230" with one of my loads and not only saw much improved consistency but got some extra fps with the shorter length. I would agree with the recommendation on using the same headstamp for testing as well.

Regards...

[ihatepickles]

For the 650 specific stuff:

• Check that the failsafe rod is setup correctly which will make sure the powder measure is fully loading up each time you cycle the press.
  
• Make sure you're getting consistent seating depth from your seating die. If each bullet is seated to a different depth, case pressure will be different.
  
• Make sure that the taper you're using is bullet diameter plus case thickness (don't forget that case thickness is doubled since the case is on both sides of the bullet). Reasonable taper should be around .451+.010+.010 +/- .002 for the round when finished and measuring at the case mouth. Over tapering the round could be changing the diameter of the bullet and making it not fit well going down the barrel
  
• Smoothly cycle the machine in a consistent fashion. As you raise the case into the powder die and then lower it, be smooth and even. This makes powder drop more consistently. Weigh each charge you throw for 10 rounds and see if you're getting consistent powder drops, if you are getting consistent drops then take those 10 specially weighed rounds and see if they chrono erratically like the other results you've had.
  

Although any one of those things could be happening, it's more likely that the powder, primer, bullet, (and possibly different kinds of brass) combination aren't working for you in that gun. Try a different powder. Try varying the charge you're using, but stay safe. You can also do a run of a single brand of brass to see if that's the issue but that's not as likely to me as "your gun just doesn't like it.

Lastly, extreme spread and standard deviation aren't the last word in load development. My .45 ACP load is 4.1 gr of Clays on a 200 gr RN moly coated lead bullet and it groups 3" at 25 yards. The SD of that load in my gun is 30 fps, go figure... but it works even though the chrono numbers look bad.

[mda]

Hello,

I just started loaded with a new Dillon 650. The powder I am using is Hogden Titegroup and the Primer is (the only onne I could get Remington 2 1/2.

To get my FPS to around 700 I had to go to 4.2 grains. The problem is that the FPS is not consistent.

Sometimes I hit a high of 750. The others, a low of 650. Thats pretty wide!

The chorono I am using is the newest CED.

Any suggestions on how I can get my 45 ACP reloads more consistent?

Your data is not really that bad, it only has a few flyers. From your data you are averaging about 705 FPS with a SD of 19. Since this is normal distributed data that would mean that 68% of the readings are with in +-19 FPS of the average and 95% of all readings are with in +-38 FPS.

Most others have already indicated possible areas which can cause spread, I.E. mixed brass, inconsistence/improper crimp, etc. The chrono can also be a source of error if using natural light. Did you use IR screens in a box?

My personal experience with TG has been that there tends to be be a larger SD then with other powders.

MDA

Edited May 10, 2009 by mda

[dajarrel]

texasdog,

I was shooting .45 in my 625 and went to the chrono at A6 a few years back. I almost went minor as my fps was all over the place. I happened to notice my rounds hanging when I was inserting a moon clip and found there was a noticeable lack of a crimp. I checked my 650 when I got home and found that the crimp die lock nut had worked loose. After I reset the crimp and tightened the lock nut back in place my normal chrono readings came back. My crimp measures from .466 to .469 on a quick measurement of a half dozen rounds.

Of the things listed in the previous post, a poor crimp has been the cause of most of my problems in the past.

fwiw

dj

[GeneralChang]

I once had a similar problem and I had no idea what the problem was until I emptied the powder measure...there was a piece of brass that fell in there somehow and it was blocking the powder flow.

[CHA-LEE]

texasdog> Work backwards and find inconsistencies in your load setup. Measure every powder drop. Is it within +/- .1 grain of your desired drop? Measure the OAL of every round. Are some longer/shorter than the desired OAL? Are you using the same brass brand and vintage (New? Once Fired? Many times Fired?). How consistent is your crimp? Any one of these things can give you fps variances.

I don't see where you mentioned which bullets you are using. Some bullets are more consistent than others. I know from my testing that .40 S&W FMJ bullets made by Zero are WAY more consistent than Montana Gold from a chrono fps standpoint. In the end it really comes down to the seal quality of the bullet to the barrel when it fires. Some bullets are more consistent than others.

Lastly, the speed and consistency at which you run the press will greatly affect the end product. I like to run at least 5 full cycles of the press at normal reloading speed before I will double check my powder drop, OAL, crimp and so on. You will get different results between doing one at a time verses chugging through the rounds at normal reloading speed.

[AlamoShooter]

Are you using the small or large powder bar? If you are trying to throw a small charge with the big powder bar it could act up on you.