load testing .223 ladder test?

[The_Hoff]

I have recently began load development of a long range precision round for my AR platform. I will be loading to mag length.

my rifle has a NATO 5.56x45 chamber so it can handle higher pressures than a standard .223 barrel. It is a true 1:8 twist 24" Heavy Bull barrel, target crown

I have tested many types of match ammo and my rifle loves fiocchi exacta match with 77 grain SMK's.

My cases are 1x fired privi partizan brass. head stamp PPU 08 5.56x45, they are crimped primers but I swaged the crimp and uniform the primer pockets. each case is tumbled for 2 hrs, deprimed, FL sized, chamfered and deburred, crimp swaged, primer pocket uniformed and the neck is cleaned with a neck brush, then tumbled again.

I am using 77 grain sierra match king bullets and varget powder, for primers i am using WIN small rifle primers. all loads are seated to an OAL of 2.258" +/- .002" this is due to meplat differences in the bullets.

for initial testing i loaded 25 rounds. 5 rounds of each charge weight.

1 22.0 grains varget
2 22.5 grains varget
3 23.0 grains varget
4 23.5 grains varget
5 24.0 grains varget

after test firing each no pressure signs were seen on any cases.

for my ladder test my local range is under repairs so i was limited to 100 yards.

1st shot is with a factory fiocchi exacta 77gr. smk. to act as a sighter and fowler. 2nd shot is 22.0gr, followed by 22.5, and so on.

I would really like opinions on my ladder test results, I am having a hard time interpreting them, I think i might need to use smaller charge increments and longer ranges.

 

[Chiller]

Re: load testing .223 ladder test?

yes and yes.....

at 100 you can hide an elephant.

Why Varget?

 

[The_Hoff]

Re: load testing .223 ladder test?

heard it was good with variations in temperature and heard some good accuracy claims with it

 

[jbailey]

Re: load testing .223 ladder test?

redo at 300.
you might have a node at 2-3-4, but impossible to tell for sure.

also, how tight can your rifle shoot groups? At 100, if you can't print 0.25 groups, the results could be just pure bullet dispersion.

 

[2ndamendfan]

Re: load testing .223 ladder test?

Why not varget??

 

[The_Hoff]

Re: load testing .223 ladder test?

I am using varget, and my best 100 yard 5 shot group with my rifle is .547"

I will dig up some pics of those groups.

i am loading up some new ammo to test and will test again today at 300

 

[Chiller]

Re: load testing .223 ladder test?

Hoff,

When shooting at 300 this is where you will want to shoot for group. You want to take as many unknows out. You want the rifle as steady as possible. you will also be serveed well to shoot all the loads on individual targets. Just my thoughts, ymmv.

 

[nhassey48]

Re: load testing .223 ladder test?

Yea .5g is a good increment for a 308 powder capacity. but you gotta think, .5 is a huge % of the .223 case capacity. I would lower it to .2 grains and start at min and go a little over max to find your absolute max. Say you were at your max at 24.0 grains. and there weren't any pressure signs. .5 g higher might be too high and blow your chamber and face up. I would use .2g increments and start at the lowest, and work up a little past max. Also, like it was preciously stated at 100y, velocity differences arn't a big deal. but once you start going further, those velocity differences really start to show which is why you want to ladder test farther. I would rec. 300y ladder test. Thats what i use for everything. Wait until the range is fixed and try again IMHO.

 

[The_Hoff]

Re: load testing .223 ladder test?

well i loaded up a new batch of ammo in .2 grain increments. going from 23.0gr up to 24.4gr. I am going to wait till range reopens to test at 300yards. I loaded 5 rounds of each so i had enough ammo to do 2 ladder tests and shoot a 3rd group with each charge to get a good feel for the loads performance.

 

[Chiller]

Re: load testing .223 ladder test?

Hoff,

Forgive my math.....how does 5 rounds of each allow you to do 2 ladder tests and a 3rd shot group?

(2) two shot groups and 1 more?

 

[The_Hoff]

Re: load testing .223 ladder test?

ohh damn i was thinking one shot per ladder test my bad lol

 

[nhassey48]

Re: load testing .223 ladder test?

Hoff,

The good thing about doing .2 increments is that it will make your second mini-ladder or group shooting easier. When you have a node that's 2.0g long, it's kinda annoying that you have that many rounds to shoot again. But, with .2g increments, you should almost have a load after your first ladder!

 

[The_Hoff]

Re: load testing .223 ladder test?

thanks, it looks like i might get a chance sometime next week is weather holds out. can't do it this weekend. I am painting my truck lol

 

[bigwheeler]

Re: load testing .223 ladder test?

Without a chrono you'll need to shoot 3 targets, any large variation in es on one
round could give you bad info. I shoot at 200 for my 223 ladder tests. I am not
looking for drop differences, just barrel harmonics. If you know your 24.0 grain
load is safe you may want to for-go the lower powder weight loads. Start at 23
and go up in .2 increments.