• If you are being asked to change your password, and unsure how to do it, follow these instructions. Click here

6.5 CM Federal GMM Factory Ammo Velocity?

Guns&Bows

Member
Joined
Jun 15, 2019
Messages
7
Location
Portland
I recently setup a brand new Ruger American GenII Predator (22" barrel") chambered in 6.5 CM. Before firing a shot I had to send the Sig Tango DMR 3-18 back to Sig for clarity issues but thats another story.

I do reload for other calibers but I wanted to get started quickly and purchased several boxes of the Federal Premium Gold Medal Match 6.5 CM with the 130 Grain Berger Hybrid OTM. I read a lot of good reviews on this ammo so I thought I would give it a shot.

These loads grouped very well at 100 yds, less than 1 MOA.

However using TWO different chronographs (magneto speed and an old shooting Chrony) I am averaging 2651 FPS. I used two chronographs just because I couldn't believe the slow speeds.

The box states 2825 FPS IIRC.

Now, I know the speeds on the box are not always reality and I am shooting a 22" barrel but don't these speeds seem pretty dang slow for this load? Like 100 FPS+ too slow?
 
Welcome to the world of the overhyped 6.5 NM! Your at 125fps slow, that load was probably shot at factory with a barrel 4-6" longer than yours, thus the inflated fps number. If Hornady allowed those numbers to reflect most rifle barrels being used for the cartridge (20-22"), it would be a lot less popular.
 
Looking at Hornady reloading APP, none of the 129-135 bullets reach 2900FPS even with a 24" barrel.
But they list a factory loaded 129 sst @ 2950 fps with a 24" Barrel.

Even Hodgdon shows a max load with 130 gr Nosler AB at 2889 fps with a 24" Barrel.

I reload and have used RL26 from the time I first got a 6.5 CM so I had know Idea that a 24" CM could shoot less than 2900 fps with a 140 class bullet. Velocities were originaly checked with a Magneto Speed and now with a Garmin. I have several thousand rounds out of my rifles ( over 3000 ) and have never put a factory load through them. I have over 12 loadings out of my old Nosler Brass. My S20 24" and My Tikka 24" both get over 2920 with 143 ELD.

As we know there are many factors beside barrel length that effect velocity.
 
But they list a factory loaded 129 sst @ 2950 fps with a 24" Barrel.

Even Hodgdon shows a max load with 130 gr Nosler AB at 2889 fps with a 24" Barrel.

I reload and have used RL26 from the time I first got a 6.5 CM so I had know Idea that a 24" CM could shoot less than 2900 fps with a 140 class bullet. Velocities were originaly checked with a Magneto Speed and now with a Garmin. I have several thousand rounds out of my rifles ( over 3000 ) and have never put a factory load through them. I have over 12 loadings out of my old Nosler Brass. My S20 24" and My Tikka 24" both get over 2920 with 143 ELD.

As we know there are many factors beside barrel length that effect velocity.
So I guess they're over SAAMI max.
 
I recently setup a brand new Ruger American GenII Predator (22" barrel")

Your new barrel has not been broken in yet and it stands to reason and a load of experience than new factory barrels rarely if ever achieve the velocity as claimed on the box of factory ammunition. The barrels used by these factories for testing accuracy and velocity are usually made by the very best barrel makers, not slammed out by the yard by the factory.

The velocities on those boxes of ammunition are achieved with test barrels having fired lots of bullets and are extremely well broken in. The chronographs being used in these tests are extremely expensive and accurate. Your new (22") barrel doesn't stand a chance of coming up to that velocity.

Call Federal and discuss this with them.
 
Lot #L338P36
22" Proof Research Barrel. I had 220 rounds on that barrel right before shooting 20-rounds of the Federal loaded Berger 130 OTMs.

1731423188445.png


Advertised MV is 2875. I would assume their test barrel is 26", but I didn't see barrel length explicitly stated. Assuming an average +/- 25-fps per in of barrel length, the difference between advertised MV and what I experienced is right where I would have guessed it to be.

I'd assume you have a slow barrel and/or you don't have enough rounds down the barrel for it to have stabilized in terms of speed.
 
I did shoot an email to Federal asking about this slow velocity. We will see if they respond. Looking at @Euler data it seems like either I got a slow batch, have a slow barrel or the barrel is not yet broken in. I really have never heard of barrel break in causing that kind of jump in velocity but I guess it could make sense. Adding more copper/fouling to the barrel could increase pressure and thus speed.

Still though I would need to go from 2651 to 2766 in order to hit the numbers Euler is getting with the exact same ammo. That is a 111 fps jump.
 

Recent Posts

Top