My first batch of 40, need some advice.

[CrashDodson]

I worked upped some rounds on my new dillon 550 for the first time.

I am using Ramshot Comp powder, small pistol primers, once fired brass (vibrator tumbled with crushed shell media) and Ibjihead coated 180g round nose flat bottom .401 bullets. Loading to 1.2 OAL. My crimp is enough to remove the bell with no obvious inward bevel on the case.

My starting load was 3.2 grains and I went up to 4.7 grains in .2 grain increments (except from 4.6 to 4.7 4.7 was recommended to me by the previous gun owner for a major PF load.) I chamber checked all of them.

I loaded 5 rounds of each. I weighed the powder after 3 cycles....and weighed again after 3 more cycles before starting each load. I'm using an RCBS beam scale.

Went to the range today and used my prochrono digital chronograph. Rounds shot from my 5" STI. I wont list all but just some examples.

3.2

760 - 788 - 781 - 729 - 746

3.6

808 - 787 - 820 - 778 - 807

4.0

858 - 854 - 852 - 896 - 862

4.4

864 - 910 - 932 - 924 - 917

4.7

935 - 950 - 949 - 958 - 932

These velocities seem to be a little extreme in their variation for the same load. I would slow fire 5 rounds (1-2 seconds per shot). Write down my string from the chrono. Collect and inspect brass and repeat. The first shot was almost always the lowest. I shot some freedom munitions 9mm through my xdm and saw only a +-5-10 FPS variation.

Is this normal or is this something I need to try and address? I made no changes to the dillon other than the powder throw while loading.

Edited October 21, 2015 by CrashDodson

[FortyOverUnder]

For ramshot comp it's a normal variation. I use 4.6gr of the same stuff for major.

[peterthefish]

Nothing to do with your press or the powder. A single digit standard deviation is usually tough to hit, and that means extreme spreads of 20-30 FPS / load.

Also, loading just 5 doesn't give the powder measure time to settle. If you want the most consistent rounds possible, you have to match headstamps, and cull the first and last 5-10 rounds out. Grab a sample of 20 from when you're running a consistent rhythm.

Either way, an ES of 40-50 FPS isn't going to make a huge difference.

Edited October 21, 2015 by peterthefish

[crazygiant]

I see no problems with those spreads. To get tighter tolerances you would have to weigh each bullet, trim all matching head stamp brass to the same length, and hand weigh each load. But that would take way to much time for the marginal increase in accuracy. What I do is I'll dial in a charge weight, cycle about 10 charges while dumping them back into the powder hopper, then load 13 rounds for each weight of powder in testing. I load 13 so I can drop 2 extreme variences and have an extra for just in case.

[Hi-Power Jack]

How was the accuracy of the rounds you fired?

[Garyshome]

Are you weighing your boolits? Are you weighing your brass? Separating the head stamps?..............

[CrashDodson]

How was the accuracy of the rounds you fired?

I was just shooting through the chronograph into the berm. I made up a few more rounds tonight I will test accuracy with.

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[CrashDodson]

Are you weighing your boolits? Are you weighing your brass? Separating the head stamps?..............

What would be the purpose of weighing my boolits and brass? I'm not weighing the rounds afterwards on my balance beam scale. I load slow, check each charged case and a double charge of 4.7 grains will overflow the case.

As for seperating head stamps I don't see the point but I'm always eager to learn something new.... I check each piece of brass for damage after cleaning. Would this be for accuracy purposes? I gauge each round and check oal/crimp on every 10 or so. I check each round for tall primers.

thanks for the replies.

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[Hi-Power Jack]

Are you weighing your boolits?

As for separating head stamps I don't see the point

Each head stamp has a slightly different capacity, so to achieve the best accuracy,

separating head stamps is a simple, yet effective, way of achieving that.

For USPSA/IDPA, very few people need the slight amount of accuracy that you

gain by separating headstamps, though.

Looks to me, like your heaviest load (4.7 grains) looks very good - it's only

five rounds, but they vary from a low of 932 to a high of 958 (26 fps), and

the 3.6 grain varies from 778 - 820; and 4.0 grains are all the same, except

for one high flyer.

1. Your sample size is not very large - I use 20 rounds over the chrono to

ascertain velocity and range. Actually, not real bad.

2. Great idea to put a target down range when you're shooting over the

chrono - get to measure velocity and accuracy at the same time

3. Not always a direct correlation between range of velocity and

accuracy (you'd think there would be). We're really looking for

acceptable accuracy, and frequently find that despite what seems

like large variations in velocity, the accuracy is acceptable.

4. I haven't found that measuring each powder charge is better than

using the Dillon powder charge. Sounds like it should be, but

measuring the weight of 3.5 grains of powder is NOT real easy

or accurate. VERY EASY to misread 3.4 or 3.5 grains as 3.5.

I think you might get better results by NOT weighing each charge

and simply use your Dillon to throw the charge for you - like you

will in real life, after your testing is over.

For accuracy, take a real firm/solid rest, and fire 15 shots or so, at

at least 20-25 yards, and discard the 2-3 flyers - measure your group

size of the center of the holes ... My guess is that you'll be happy

with the accuracy of ammo reloaded on your Dillon, including using

their powder measure.

Good luck with it.

[CrashDodson]

1. Your sample size is not very large - I use 20 rounds over the chrono to

ascertain velocity and range. Actually, not real bad.

-Good idea. In the future I will load more rounds to chrono

2. Great idea to put a target down range when you're shooting over the

chrono - get to measure velocity and accuracy at the same time

-Good idea. I was just so excited to finally try out my new loads that I didnt think to setup a target as well. I was worried about not shooting my chrono

4. I haven't found that measuring each powder charge is better than

using the Dillon powder charge. Sounds like it should be, but

measuring the weight of 3.5 grains of powder is NOT real easy

or accurate. VERY EASY to misread 3.4 or 3.5 grains as 3.5.

I think you might get better results by NOT weighing each charge

and simply use your Dillon to throw the charge for you - like you

will in real life, after your testing is over.

-Just to clarify. I am not weighing each charge. When I make a change to the powder messure I cycle it 3 times, dumping the powder back in and weigh on the 4th...then repeat. If both look good I proceed to load. I have a light over my press and I visually inspect each charge after that. If I was trying to weigh each charge on my balance beam i would go crazy

For accuracy, take a real firm/solid rest, and fire 15 shots or so, at

at least 20-25 yards, and discard the 2-3 flyers - measure your group

size of the center of the holes ... My guess is that you'll be happy

with the accuracy of ammo reloaded on your Dillon, including using

their powder measure.

-Thanks. Hopfully I can try this at the range if it dries up this weekend

Edited October 22, 2015 by CrashDodson

[SWprotected]

I don't see any problem at 4.7 you are at 170pf avg. Which is good for major. Your es is only 26fps I bet your loads will shoot just fine.

[zzt]

CD, I buy my 40sw brass. It is mixed head stamp, cleaned and tumbled. I don't sort head stamps. I don't measure case length. I really don't do anything except load them. I use a different powder than you do, but I always get SDs in the single digits (4.8~7.8 range) as long as I use 175 or 180gr bullets. I don't specifically weigh charges or anything else. I just take a random 20 out of the reloading tray and chrono them.

Here are some chrono pointers. First your sample size has to be at least 10 to give you any valid info. 20 is better. To get the most accurate results, your shot has to be parallel to the plane of the sensors and directly down the axis of the chrono. Even the slightest variation will show a surprisingly large variation in velocity. I aim at the same spot every time, so I get consistent results.

I've never used Competition, so I can't help there. I did try a range of powders out when I first started reloading 40sw. I found e3 to be the most consistent, the least temp sensitive, and accurate. So that's what I settled on. My Limited Major load is mixed range brass, 3.7gr e3, WSP, and 180TC Falcoated bullet loaded to 1.126". It makes 172PF.