Extreme spread in velocity

ChetStafford

I loaded some 50gr vmax's and 50gr nos. ballistic tips for my .223 I got as much as 197 fps deviation out of one string

They were loaded with w748 and Benchmark I got large amounts of deviation on all the different charges on both powders

Winchester cases and wsr primers Could it be the primers?

I weighed each powder charge all of the rounds were 2.260 oal

I am stumped any help will be greatly appreciated

perry shooter

Hello just a thought but I would try a box of factory match 22 long rifle if you have a 22 to use as bench mark to see if your Chronograph is working correctly some times you may have a problem in one area and it will drive you nuts looking at the wrong cause. just a thought.

bpost

I have also gotten poor Chronograph results. Some were very similar to yours. However when I looked at the group and it was one teenie-tiny ragged hole I stopped worrying about it.

Wise men told me the chronograph is a tool, the target tells the tale.

A 197 FPS deivation could be from several factors. If your sure the chrono is not a liar and you have crappy groups I would switch primers first, check neck tension next, weigh and sort cases third.

Please keep us posted.

ChetStafford

The thing that makes me believe the chrono is I did take a box of factory 55 gr umc 223 amo and it only ran 47 fps deviation but the gun seems to love any round that I put through it I actually did .75 groups out of it with the worst loads the gun is a real shooter

shooter93

A couple of hundred fps doesn't mean to much at 100 yds. with high velocity cartridges. Back the target up to 300 yds. or so and you'll see the difference. Extreme spread means more the farther you shoot.

JustC

how hot was the barrel/chamber?? if you load rounds into an already overheated chamber/barrel,..the new round acts as a heat sink,..and the round heats up. This changes the burn rate of the powder, making more pressure etc. The time it is left in,..being different from the next round can allow one to gain more temp than the next, so the velocities will be all over the place.

also, as stated, try examining neck tension. If you are at .001" or less,..then you may need to bump the tension up some for more consistent projectile release.

how old is this powder? was it opened and stored for a long time?

ChetStafford

The point about the heat struck a bell I was running them pretty fast I guess since it is a heavy barrel I never even considered heat being a problem

That make alot of sense now that I think about it two primers in one string were cratered

None of the powder is more than 3 months old I have 2 223's

This one is a new one and I was trying to find the right load for it wich may be pretty hard because it seemed to like almost every thing I threw at it

ChetStafford

I found taht I had my resizing die adjusted wrong and ruined 50 pieces of brand new brass I think that had something to do with it!50 head seperations or at least they were very thin about 1/2 an inch ahead of the rim

I also switched primers and went shooting today got some pretty good results with a 50gr nosler bal. tip and 26.5gr of benchmark I got.4 groups and an extreme deviation of 46 fps and an average vel. of 3420 fps this is a max load and it is also the load my rifle liked best I also loaded som 40gr nosler bal. tips again my gun liked thmax load best 28gr of bench mark I got 19fps deviation and a 3745 average velocity and .435 groups

win case
federal 205 primer
benchmark powder