Home Forums Reloading Big Game Rifles low velocity in 243 Winchester

I have 2 youth rifles in 243 Winchester. One is Remington 700 youth. The other is T/C Venture compact. Both have 20" barrels and are less than a year old. Accuracy with every load tried is averaging from 3/4 inch to 1 1/2 inch at 100 yards. No complaint there.
In working up deer hunting loads for these rifles I am getting very low velocities compared to published data. I am loading 1/2 gr under max published data. I am working up loads for 95 sst and 100 sp Hornady bullets using H4831sc, imr4064, and imr4350. The chronograph velocities are running 200 fps to 300 fps lower than published data by Hodgdon and Lyman. The highest fps is 2705 using H4831sc with 95 SST bullet. Both rifles are giving fps readings within 25 fps of each other. I realize that I am shooting out of 20" instead of 24" bbls. What is your experience with 20 bbl velocity?

As a rule of thumb, the greater the bottle neck the more barrel length matters. You are giving up 4" of barrel vs. most published data, so that sounds about right.

I carry a .243 Bullberry, 20" barrel a lot as a jeep gun, here on the ranch, kills everything I point it at using 85 gr. bthp, H-4895, whitetail,axis,and some big pigs,shoots under 1" at 200 yrds,want to go faster use a smaller bullet. Rio7

Youth model, 3/4 " and you are worried about velocity being off book out of 20".

Give him a few more years of chronographing and he will learn the books are just a guide. If the books were right for our guns, no one would buy chronographs.

I'm using a barrel that was a Rem 700 take-off I had my gunsmith fit to my action and cut off at 20". Depending on which 95-100 grain bullet is being used, 41 grains of IMR4350 is giving 2830 to 2890 fps averages as reported by my Oehler 35P.

antelope sniper,

And if nobody had chronographs, they'd assume their rifle got the highest velocity listed in any "book." And they'd go out and kill stuff.

This is exactly what happened before everybody could buy "personal chronographs."

Lots of people still out there doing that exact thing MD.
I've had more than one friend that was shocked to learn how much slower his handloads were compared to book velocities after running them across a chronograph
Some had been blissfully slaying game for years with slow loads

You can have the fastest bullet in the world won't due any good unless you can hit what your shoot at were it counts. rio7

PaleRider,

Yep, that happened a lot when the first chronographs appeared. I bought mine in 1979, and when at the local range other shooters would often approach me, asking if they could fire a few rounds to see what the velocity was. They were invariably disappointed, even with loads they'd been slaying deer and elk with for years.

In fact it happened to me, with that same chronograph....

MD,
I have to confess to having BTDT myself back in the day

John, I still remember when I got my first Chrony in the early eighties. My exquisite 270 load with a 140-gr Hornady BTSP with H4831 was finally "clocked." I had shot numerous antelope and mule deer with it and it was very accurate--it was the berries!

When a five shot average showed 2700+, I was aghast and went ito a mild depression. Though the bad dreams have ended I still remember it.

When I first got a chronograph with skyscreens I too was a bit disappointed with some of the velocities my loads were showing.

So, I moved the screens 1" closer together and that put the velocities back where I wanted them....

Now THAT'S out-thinking the machine!