7 PRC/7SAUM Velocities

[dogz]

I am gettung a barrel chambered soon and looking for velocities people are getting in these two cartridges with different barrel lengths. Specifically 20"-24" barrels with 180 grain bullets. I am not looking for velocities on loads that primers fall out after two firings. Thanks in advance.

Consider taking a close look at what the Hodgdon sight has to say about the two rounds. Good thing about Hodgdon is that they use actual pressure tested loads. Without that we're all guessing. They'll give you your best idea as to intelligent speeds to be running things.

Otherwise it's just too darn easy for a proponent of one or the other to pound the **** out of one or the other and yet mysteriously they're not seeing pressure signs.

Speed always equals pressure and pressure always equals speed...........just a thunk.

Fire away boys.........

 

[Idaho Lefty]

I reload for everything I shoot. How far out have you poked elk with the saum with 20" barrel and how did it perform? I have a bunch of 180 ELDM my 28 Nosler didn't like them though. Hoping something else will.

My son's, 24 inch Proof Barrelled Tikka, in 7 PRC with, ADG Brass, F-210M Pr's, shot the 180 gr. ELD-M's into, a .311 dia., 5 shot group, using StaBall HD powder at, 3,002 FPS ( it was, a fairly HOT Load at slightly OVER Max chg. but SAFE, in His Rifle ). Hogdon HAS Data, on StaBall HD.
The ELD-M's ARE, very accurate Bullets, when,.. "Tuned" !

 

[2buffalo]

So what I am seeing here is the SAUM in a 26" barrel will get you roughly 2950 a 22" barrel will get you 2850 and a 20" barrel will get 2725. Looks like you lose 100 fps in the first 4 inches and 125 fps in the next 2 inches. So it's losing 25 fps per inch for the first 4 inches and jump to around 60 fps loss under 22". Does this sound correct?

 

[Ucsdryder]

So what I am seeing here is the SAUM in a 26" barrel will get you roughly 2950 a 22" barrel will get you 2850 and a 20" barrel will get 2725. Looks like you lose 100 fps in the first 4 inches and 125 fps in the next 2 inches. So it's losing 25 fps per inch for the first 4 inches and jump to around 60 fps loss under 22". Does this sound correct?

Too many variables. I had my 20" up to 2800 with ejector marks. Hard to say unless you have a lot of data. I think a rough estimate would be 50ish faster on the prc.

 

[Rick Richard]

So what I am seeing here is the SAUM in a 26" barrel will get you roughly 2950 a 22" barrel will get you 2850 and a 20" barrel will get 2725. Looks like you lose 100 fps in the first 4 inches and 125 fps in the next 2 inches. So it's losing 25 fps per inch for the first 4 inches and jump to around 60 fps loss under 22". Does this sound correct?

I think BarbourCreek has a video out there where they tested what your referencing. And, the test concluded the same results…drastic decrease in fps below 20 inches.

 

[Jakeweb09]

So what I am seeing here is the SAUM in a 26" barrel will get you roughly 2950 a 22" barrel will get you 2850 and a 20" barrel will get 2725. Looks like you lose 100 fps in the first 4 inches and 125 fps in the next 2 inches. So it's losing 25 fps per inch for the first 4 inches and jump to around 60 fps loss under 22". Does this sound correct?

Id say it's barrel/powder (and person loading/reading pressure )subjective but yeah usually you'll lose more severely as you get shorter. That being said the Saum is known for being very efficient in shorter barrels. Probably lose fairly steady 20-30fps per inch until around 20" then it'll start dropping more significantly

 

[Idaho Lefty]

I'd personally NOT go much under, a 20- 22" with either, unless you want to make, a LOUD,.. .30-30,.. out of, it,. LOL !
A PVA Jet Blast, 3 Port Brake, tamed my son's Recoil, WAY down, WITHOUT the Horrible,.. Blast / concussion at, the Shooter.
The Tikka / Proof 24", Rifle in, a New Stocky's Carbon Fiber stock, weigh's, 8.4 Pounds with, a 4.5 x 16 Zeiss, Conquest scope.

 

[Trm82]

7 saum , adg brass , RL 26 61.5 gr , 210 M primer , 175 elite , 2955 fps In a 24 inch barrel

 

[crashlanding]

I think BarbourCreek has a video out there where they tested what your referencing. And, the test concluded the same results…drastic decrease in fps below 20 inches.

I went looking for the video here on the forum not to long ago and you couldn't access it anymore. Specifically the 7 prc with 2" increments cut off at a time, it was a good video

 

[2buffalo]

I think BarbourCreek has a video out there where they tested what your referencing. And, the test concluded the same results…drastic decrease in fps below 20 inches.

I will have to look for that. What length and barrel are you building?

 

[Rick Richard]

I will have to look for that. What length and barrel are you building?

22 since I am going to run suppressed….whenever it gets out of jail.

 

[dogz]

So what I am seeing here is the SAUM in a 26" barrel will get you roughly 2950 a 22" barrel will get you 2850 and a 20" barrel will get 2725. Looks like you lose 100 fps in the first 4 inches and 125 fps in the next 2 inches. So it's losing 25 fps per inch for the first 4 inches and jump to around 60 fps loss under 22". Does this sound correct?

25-30 fps loss/gain per inch added or subtracted is a good place to start. The more over a round the more it'll lose, the less over bore then the less it'll loose. IE. a Big 7 (long or short case) will loose more fps per inch than say a 338 WM or a 375 H&H.

I'd build for balance and feel for you and not worry about the speed loss but that's just where I'm at. My 70/7WSM is 22" and supressed, honestly I wouldn't mind bobbing it 2" more.

 

[gillettehunter]

24 inch 7 SAUM with RL 26 and a Berger 180 HVLD. Right at 2900 fps. Killing machine. Likely over 50 animals now including 3 eland.
Bruce

 

[crashlanding]

22" 7mm prc, adg brass, 66.0 grains of rl26, federal 215 and a Berger 180 hybrid, 2900 fps and that didn't top out, still working up. Just clocked it today