.375 Ruger on the Chronograph

OK, I recently read something about the Hornady claims of velocities being "padded" and the acual measured velocities not matching that in the real world. That I wanted to see for myself and wanted another excuse to shoot my new rifle. So I borrowed my neighbors chronograph and went to the field. The rifle I have is a new Ruger Hawkeye African with a Nikon Buckmaster 3-9X40 scope and the ammunition I used for the test was Hornady 300gr. DGS. My buddy took his Winchester Model 70 chambered in 7mm Mag. and fired Monarch brass cased 150 gr. ammunition, it was on sale, which we also put through the chronograph as a "control" for the test. Now I know that ballistic information printed in ammunition catalogs are fired through a 24" test barrel, etc. but I wanted to see how the ammunition did through my rifle and how far off it really is. The chronograph was approximately 10ft from the muzzel and here is my results by shot.

Shot 1 = 2658
Shot 2 = 2611
shot 3 = 2570
shot 4 = 2572

Hornady advertises at the muzzle to be 2660.

The 7mm hung around 2820fps. with the Monarch ammo, which I don't have their data for, but Hornady says theirs does 3035fps. in the standard cartridge with a 154gr. bullet, so I believ that the chronograph was working accurately enough for my non-scientific test. The weather was in the 50's and windy. Both rifles were very accurate and fired well although the modle 70 had some feed issues with the Monarch ammo. So my conclusion is that Hornady didn't really "pad" anything and you should expect their ammunition to perform very close to advertised. This was just a fun test to perform, and gave me a target velocity for my handloads once I get the dies made. Anyway, hope you all find this as interesting as I did!

Seems like a large variation in velocity, I guess that's what you get with factory loads. I've only used a chronograph once and my handloads only varied by about 10fps if I remember correctly.

Did you clean the barrel inbetween shots?

There's a lot of factors that can effect the bullet speed. Mostly, factory velocity information is based on a "test" barrel. Usually it is a 26 inch which gives slightly more velocity. The bore is usually "tight", so very little propellant gas slips by the bullet. The chamber is head spaced to the case, so the case seal is optimized.

Conversely, factory rifles have "generous" chambers and bores that can let the expanding propellant gas slip by.

This is not unusual. Factory velocities are usually recorded under optimum circumstances.

One more reason for hand loading to optimize bulllet, powder, seating depth and head space to your own rifle.

Originally Posted by Bushbuck

Did you clean the barrel inbetween shots?

No, just shot through the Chronograph. Honestly, this was my first time doing this as I just recently discovered my neighbor owned one. I will be buying one eventually though as I think it is a valuable tool for reloading. I really had a good time doing my little test and posted it to learn a little more about chronograph use and so on, as well as posting the results for the .375 ruger cartridge from the field. You guys have not let me down! Thanks for the replys'!

Originally Posted by browningbbr

There's a lot of factors that can effect the bullet speed. Mostly, factory velocity information is based on a "test" barrel. Usually it is a 26 inch which gives slightly more velocity. The bore is usually "tight", so very little propellant gas slips by the bullet. The chamber is head spaced to the case, so the case seal is optimized.

Conversely, factory rifles have "generous" chambers and bores that can let the expanding propellant gas slip by.

This is not unusual. Factory velocities are usually recorded under optimum circumstances.

One more reason for hand loading to optimize bulllet, powder, seating depth and head space to your own rifle.

Isn't it also true that a bullet will move slower on a cold day and faster on a hot day?

It is true that if your ammo gets cold, there will be some effect on velocity. I've noticed a few feet per second difference in average velocity with my 300 win mag.

In like rifles with same barrel lengths, they are extremely close on my chronograph. I have chronographed both the 416 Ruger and 375 Ruger along with my H&H and 416 Rem. No difference. all guns were custom Mausers in my case.

Some of the 77s have short tubes and probably lose a bit of velocity, but would be insugnificant in the field IMO..

As to Hornady ammo, I wouldn't doubt that it weak, most ammo manufacturers leave themselves some room to protect themselves from those ridiculas lawsuits. I have not chronographed Hornadys loaded ammo. I only shoot handloads.