Factory ammo speed : the reality

The chances of getting claimed velocities from factory ammo and book speeds from handloads rise exponentially with high quality and custom barrels with tight chambers, and bullets seated near the lands due to short throats or planning. It's not that unncommon to match the book with starting loads. Tests that show that many rifles don't match advertised speeds with factory ammo also show that some of them do.


Conversely; the odds plummet with sloppy chambers and production grade barrels that internally look
like the illegitimate offspring of a sewer pipe mated with a railroad track.

If you are going to manufacture ammo with the highest priority being that it is safe in every rifle, it stands to reason that it is going to be slow in a lot of them. Or in cowboy logic, if none of them are overloaded; most of them are underloaded. Or if you're going to load fast you better load light. Or in racer logic, the cheapest probably wont be the fastest.
 
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I have chronographed thousands of loads over the years. If one thing is eveident, it is the fact that every factory
load is a rule unto itself. Occasionally, one will make advertised velocity in a factory rifle, but not usually.

As far as handloads go, it is folly to expect the velocities shown in the manuals to be YOUR velocities in YOUR rifle.

One gets surprises from time. I chronographed some offshore ammo [Magnum] that was leaving the 22" muzzle at
50 fps faster than the advertised velocity. Also graphed some domestically loaded 300 Win Mag ammo at 200 fps
slower than advertised [24" barrel] Only way to know is to run it across a chronograph. lol. Dave.
 
I was surprised the first time I tested what factory loads I had on hand with a chronograph. A couple were close, a couple were way slower than advertised, none were over. I have been able to pickup as much as 300fps with handloads, and also not been able to match factory within 100fps.
At the moment I have one that factory is 150 low, and handloads haven't got to that level yet, either, with 1 gr over on the handloads. Another couple that are about bang on with factory or handloads. The bulk of them were done on an Oehler 35, so, odds are, it wasn't the chrono doing anything weird.
 
more added :


7mm Rem Mag, Remington 150gr Core Lokt ~ 3110 fps claimed
24.4" Tikka T3x ~ 2993 fps

7mm Rem Mag, Hornady American WT 154gr Interlock ~ 3035 fps claimed
24.4" Tikka T3x ~ 2744 fps

7mm Rem Mag, Federal Premium 160gr Nosler Partition ~ 2950 fps claimed
24.4" Tikka T3x ~ 2800 fps

44 Magnum, Federal American Eagle 240gr SP ~ 1230 fps claimed (7.5" pistol test barrel)
16.5" Marlin 1894 ~ 1761 fps
 
more added :

308 Win, Federal Fusion 165gr ~ 2700 fps claimed
18.8" Ruger m77 ~ 2549 fps

308 Win, Nosler TG 165gr Accubond ~ 2800 fps claimed
18.8" Ruger m77 ~ 2565 fps

308 Win, Hornady Superformance 165gr Interbond ~ 2840 fps claimed
18.8" Ruger m77 ~ 2650 fps

308 Win, Federal Premium 180gr Nosler Partition ~ 2570 fps claimed
18.8" Ruger m77 ~ 2424 fps

308 Win, Federal Premium 180gr Trophy Bonded Tip ~ 2620 fps claimed
18.8" Ruger m77 ~ 2441 fps
 
Dave nailed it...the ONLY way to know what your ammo is doing is to chronograph it. And I'll add that the only way to know what it is doing at distance is to shoot it at distance.


Kudos to Mark for posting up all these results. Something interesting to think about in the dark of winter.
 
I’m an info nut. Good on you for keeping such detailed records, little bit jealous that my shooting log isn’t as complete. When I look at those number I see a direct correlation between barrel length and velocity. Claimed velocity shot through one real life through another. Of course there’s chamber, throat and barrel quality variations as well. But the over riding commonality is barrel length and velocity.

Its interesting how many shooters go through such lengths to avoid, or find another reason for ballistic variations. In my mind the chronograph and especially one like the labradar working at muzzle and independent of the gun so as to allow use every session.

I’ve never understood the reloaders who create a load and then chronograph the “chosen” load. Why not chrony all of them? If you’re shooting factory only, why trust what the box or website says? It only really matters what’s going on real time real world in our guns. If your gun is shooting 200-300 FPS slower than the box says because you have a 20” barrel and the load was tested in a 26” or whatever, they’re not ripping you off or lawyering anything. It’s physics. At least with the chrony you can know the velocity and work out the ballistics, create a chart etc, start shooting and become proficient at whichever ranges you’re able.

Velocity is pressure as closely as the home hobbiest is able to measure. If a manual lists a load at 3000fps out of a 26” test barrel, and you work up the same load but only get 2700fps or whatever out of your 20” mountain Carbine. It doesn’t mean they “lawyered” the manual and you just keep adding powder. It means if you screwed on a 26” barrel the same load would clock much closer.
 
I just finished running some handloads for two 6.5CM rifles over the magnetospeed. The same load produced a difference of 90fps in two rifles with the same length barrels. Measuring the distance to the lands, the rifle producing the higher velocity has a much shorter throat. The load produced less velocity than what the manuals predicted in one rifle, and more in the other rifle.
 
I use a shooting chrony all the time but don't trust it so I prefer to shoot at distance and extrapolate the velocity from the real world results. I use the chrony for spreads and deviations but not for actual velocities as I see too much variations in velocity readings day to day and even through the same day with changing light conditions. Those LabRadars look nice but at this stage of life I don't think I will invest in one as I already have loads worked out for all my guns and I don't see me getting very many more.

I just built an LED light source for the chrony to see if it was the light that was causing the variable readings but have not done much testing yet. If it helps I will start a thread on it.
 
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Great thread. The claims made by the ammunition manufacturer are usually slower than what the chronograph reads and the readings from the Lab Radar and MagnetoSpeed can be much slower than a Chrony in bright sunlight. I did find that the LED lights helped get accurate readings when using the Chrony indoors.
Another thing that the chronographs are great at is showing whether book loads are close to their listed velocities. I recently did some work with a Winchester Model 70, in 270 WSM, with a 24" barrel and was really surprised at the Nosler Manual results when working up a load for the 150 LRAB with H 1000. I had the bullet seated at Noslers test length which put the 150 LRAB 0.056" off the lands in their 24" Wiseman Test barrel. Nosler showed a Max load of 63.5 grains, H 1000, giving 3068 fps but my rifle clocked only 2808 fps over the Lab Radar and got 2863 at 65.0 grains where the case had reached max stretch at the 0.200" datum and primer flow was greater than the factory rounds I tested.

Factory rounds tested:
Win 150 PP - Claimed 3150 -Averaged 3146 and were a bit tight but had Zero Primer Flow and case datum expansion just over Saami Max Case.
Win 140 Fail Safe- Claimed 3125 - Averaged 3010 with case datum expansion just over Saami max case dimension.
Federal Premium 140 Nosler AB - Claimed 3200 - averaged 3147 with case datum expansion to Saami Minimum Chamber so a bit hot.
Federal 130 Blue Box - Claimed 3250 - averaged 3301 with case datum over Saami Minimum chamber by 0.0004'
Federal Premium 150 Nosler Partition - claimed 3100 - Averaged 3201 with case datum expansion 0.0005" over Saami Minimum chamber.

The Winchester150 PP had the best group of 0.75 " at 100 yards and the brass had the least HS and stretch at the base datum/
The Federal brass had as much as 0.008" HS and ran over pressure for the brass which likely caused one brass to split back from the shoulder as shown in this picture.
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As well the sharp shoulder had these wrinkles.
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Excellent work and data gathering. I admire your dedication and collection of firearms.

A lot can be gleaned from the data, however, problem i see for me, with the data is it's a point in time. One time.

Case in point, I have a 223 factory load that shoots 1/2 MOA out of one of my rifles in moderate temperatures. I cannot use it for hunting in winter, because at -20, the load drops 4" from POA and groups open up to 2+" at 100 yards. No idea what the velocity, but it's dropping significantly in the cold!
 
Slimbo said:
Would you mind elaborating on that?
Click to expand...

You shoot groups at known distances and measure the drop. You can then extrapolate the velocity and other parameters from there using your known data such as projectile weight and BC. It is also the only way to see how said loads are going to truly perform at distance.
 
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