Home Forums Hunting & Shooting Ask The Gunwriters Factory Ammo and Claimed Velocities

Some factory stuff is a big disappointment in the velocity department.
Notable exceptions, in my experience, are:

.300 Wby factory, 165 gr. Barnes TSX- Adv. vel. From a 26 in. Bbl- 3330 fps, clocks 3390 fps in my Mk V.

Federal Vital Shok 270 WSM, 140 gr. Accubonds, adv. vel. 3200 fps, run 3269 fps out of my 24 in. PacNor barrel.

This thread is very much like the ones complaining about loading manual data being optimistic.

I can assure everybody that recent factory ammo reaches the velocity advertised (or very close to it) in factory test barrels. The fact that it doesn't in other barrels is caused by many things, including looser factory bores and, sometimes, chambers. Then there's barrel length, and the temperature when you shoot the ammo.

Another factor is that "personal" chronographs sometimes aren't all that accurate, especially under varying light conditions. The ones at the factories are far more accurate, and used under consistent indoor lighting.

In fact velocities in different factory barrels vary considerably. I've chronographed the same ammo in two different factory barrels on the same day, over the same Oehler chronograph, and it's common for one barrel to average 50 or even 100 fps faster than the other.

So how in the hell can the factories "predict" how fast their ammo is going to run in your barrel? They can't. Like loading manual data, factory listed velocities are a record of what the ammo does in their test barrel, over a very accurate chronograph, under controlled temperature conditions.

I used to see a lot more slow factory ammo in the days before most avid handloads owned chronographs. It doesn't happen much anymore, but when it does it isn't due to the factories cheating.

+1, JB spot on!!!!!!!

Last one I did a few weeks ago:

Hornady Superformance 154 gr IB 7mag published velocity 3100fps
Sako L61R avg velocity from 10 shot string was 3112 fps
Tikka 695 avg velocity from 10 shot string was 3067 fps
both have 24" barrels

Cheers JB, glad to hear it. So assuming a good quality tight barrel and a well cut chamber, it's reasonable to expect ammo to perform as it claims it does. Looks like the data that helps me make my decision!

When I bought my Custom Chronograph in early 1981 I think I was the only guy in the valley with a chrono. It would attract attention at the range, and frequently guys would come over and ask if I would run a few rounds with their rifle over my chrono.

After a while, especially with guys packing any cartridge with "magnum" included in the name, I learned to first forewarn them the velocities they were going to see was probably going to be quite a bit less than advertised factory velocities.

Once I even had some disappointed magnum shooters question the ancestory of my chronograph......

Federal Premium ammo that I bought in the late 70's and some more in the early 80's in 270W with 150 NPT's never hit 2800 fps.

Remington, Winchester, Federal factory 150 grainers in 7mmRM would usually chrono right at 3000 fps.

Most 300WM 180gr factory ammo would chrono less than 2800fps.

And remember, the Custom Chronograph didn't care about no stinking light--it used the paper-metallic screens.

Sure wished they still made those screens, 'cause I still have that chronograph.........


Casey

Casey,

I purchased my Custom Chronograph a couple years before you did, and I got both the paper/foil screens and light screens. For what it's worth, the light screens seemed to read more consistently than they have on many other chronos since. One of the first things I did, in fact, was shoot the same ammo over both the light screens and the paper screens--and got the same average, within a couple fps.

My CC eventually died, and though the guy who made 'em said he could repair it, it didn't seem worth it. I tossed it a few years ago, along with a bunch of the paper screens! Dang....

&$^#$%#^%&*%^^*%*(^*(&^*(&^)&^*()&% DANG IS RIGHT!!!!!!

After buying screens for 10 years, the manufacturer (he was quite the entrepreneur and a hysterical guy) said he was going out of biz and didn't have any more screens, but pointed me to somebody else who was making the screens. So I bought a 1000 of the "aftermarket" screens--about every other one was a dud, even though it lit up the dial correctly. I still have those bum screens........

Oh well, I eventually ended up with a M35, and currently a CED M1 with the IR setup--which doesn't need light either.......


Casey

I think we fail to appreciate how much the tiny difference in volume between a SAAMI minimum spec chamber and a maximum spec chamber can make in the resulting pressure and MV. For liability reasons, the bullet manufacturers would be crazy if they didn't use proof barrels that leaned to minimum spec side, and the gun makers would be crazy if they didn't favor building max spec chambers for the same reason. Imagine the legal dustup if Hornady developed a commercial load using a max spec chamber and Savage built a rifle around it that used a minimum spec chamber.

Then there's the fact that different lots of powder tend to have slightly different levels of 'potency.' And gunpowder likes to absorb moisture. So unless you live in Arizona, and unless you just broke the seal on that bottle of powder you're loading from, a given volume of powder is going to weigh a little more, which means a given charge weight has less 'potency.'

And it doesn't help matters that the biggest-selling brand of chronograph also happens to be the one with the most marginal performance. Caveat emptor.

I once heard of a guy that bought four M-70 Winchester 30-06s, new, at the same time, back in about 1960.

He shot all four enough to determine which one was the most accurate with his preferred factory ammo. He kept that one, and sold the other three as used.

That was in the days before personal chronographs. Today, if one wanted the most accurate and the fastest rifle, it might take more than four rifles to arrive at the solution.

I know a guy today that owns a fairly large gun shop. He tries out quite a few new guns, then sells them as used, only keeping the exceptional ones for his personal collection. It must be nice to have that luxury.

Other than what Mule Deer said, I don't think you can predict it, there are too many variables.

I don't shoot factory ammo except for chronographing someone else's stuff. Last year that amounted to shooting up a box of 300 WM for sighting in a friend's rifle with a new scope and, then, reloading the brass. They were 180 Win. PP, which averaged about advertised vel. But, the extreme spread was something like 100 fps! Most were close to the promoted 2960 and about 5 were well over 3000... a couple hitting about 3050!

A number of years ago, I sighted in another friend's 270 Win with 150gr Federals. Most didn't make 2800 from a 24".

Then, there was my experience with a new .35 Whelen. I wanted to take it hunting before the dies came in, so I bought a box of 250s. As advertised they were supposed to make 2400 from a 24". They averaged 2247 from my 22".

The only 340 WBY factory 250gr round through mine was about 2840 fps. My handloads were averaging 2997.

But, I agree, I think factories are more aware of customers expectations and are generally doing a better job with their ammo.

Edited to add: The range, at which I've been a member for over 20 years, now has over 700 members, the vast majority of which are hunters. Many are handloaders, but few of those actually chronograph their loads!

Bob

www.bigbores.ca