The Nosler saami version the head space dimension is .014 shorter. There are various internet theories on why this happened. One is that they wanted to make sure anyone fire forming AI cases from regular 280 brass would not get excess headspace. As a result the old dies will not push the shoulder back on saami spec brass. The new dies should not be used on the old chamber brass or you can over size it.if you see Nosler 280 AI or 280 AI saami it is the new chamber. All production rifles and ammo are made to saami spec chamber.
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280 AI
- Thread starter cajun
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Rocketeer77
Well-Known Member
You lose around 25 fps per inch according to genuine experts, so not a lot in reality
Rocketeer77
Well-Known Member
Be good to see some science to back that up, slower powders with longer barrels definitely give better velocities in the real world
I can give you MV's with 140's and 160's (Factory ammo) with a 17" barrel.
I shoot short 14, 15, 16, 17, and 18 inch barrels a lot in about every cartridge you can imagine, and I tend to use the same powders that folks that have longer barrels in the same cartridge.
In cartridges like the 7mm Dakota, I DON"T use magnum primers.
2961 with 140's and 2640 with 160's. I expect with reloads, I could bring up the 160 grain (17" barrel).
Ditto to what @eoperator said.
Some real world data with short barrels...
15" 20 BR with 55's and Varget - 3173 fps
15" 223 Rem with 77's and Varget - 2675 fps
15.9" 22 GT with 88's and RL26 - 2940 fps
18" 22 GT with 88's and RL26 - 3073 fps
14" 25 Creedmoor with 110's and H-4350 2726 fps
18" 25 PRC with 131's and H-1000 3168 fps
18" 26 Nosler with 147's and RL33 (210M primer) 3045 fps
18" 284 Winchester with 162's and H-4831sc 2600 fps
18" 300 RUM with 230's and Retumbo (Fed Mag primer) 2825 fps
14.5" 308 Winchester with Factory TAP ammo 168's at 2375 fps
18" 6 Creed with 103's, H-4350 at 2893 fps
15.75" 6 Creed with H-4350 and 105's at 2780 fps
16" 6 Creed with factory 103's and 108 's 103=2791 fps and 108=2704 fps
18" 6.5 PRC with factory 143's at 2818 fps
18" 6.5-06 H-4831 sc or Hybrid 100V (Can't remember know) @ 2880 fps
15.9" 6mm-284 with 90 grain AB's and H-4831@ 2900 fps
18" 7mm SAUM with 162's and H-1000 @ 2650 fps
18" 7mm Dakota with 175's and RL33 (CCI BR primer) @ 2900 fps
15" 6mm-6.5x47 Lapua Improved (Long Dasher) with H-4350 and 105's at 2800 fps
15" 6.5x47 Lapua, Varget and 130's at 2523 fps
17" 6.5-284 with H-4350 (210M) and 140's at 2784 fps
15.75" 308 Winchester with 155's and H-4895 @ 2555 fps
15" 22-250 with 50 grain V-Max @ 3100 fps
17" 6.5 Creed with factory American Gunner 140's @ 2550 and with factory 147's @ 2470 fps.
18" 22 Creed MRP and a 82 grain bullet @ 3105 fps
15" 6BR with Varget and a 105 @ 2380 fps
15" 221 Fireball improved with IMR 4227 @ 2639 fps
14 or 15 inch 20 Vartarg with H-4198 and 40 grain bullet @ 3271 fps
15" 6XC with H-4350 and 107's at 2731 fps
20" (might be a 18") 7mm LRM with H-1000 and 180's at 2775 fps
18" 6.5-284 with 147's and H-4831sc 2520 fps
WYO300RUM
Well-Known Member
DRock
Well-Known Member
I will add my data to OP's question. I am shooting 22" custom Fierce rifle and the 155gr TLR bullet. My MV is 3005 with RL16 and large rifle primers. I tried a lot of different combos and that produced the best accuracy but not necessarily the best velocity. I got over 3100 with RL16 but the accuracy was phenomenal at lower velocity.
Rocketeer77
Well-Known Member
Would be great to see the one rifle running powders faster to slower while safely maxed out to have comparison results with differing burn rates. Velocities and accuracy results this would be very interesting to see. Something I would like to try but don't have the time unfortunatel.
Teekerguy
Well-Known Member
If you wanna take the time you can neck down 30-06 and run lapua
Every barrel is a bit different, but I found this interesting.
Velocity Testing | Thompson Center Barrels | Match Grade Machine
Velocity Testing | Thompson Center Barrels. This comprehensive guide offers info on today's top cartridges. Come learn with us!
Rocketeer77
Well-Known Member
The Myth of Barrel Length and Velocity Loss :: Guns.com
One of the biggest myths that I have heard over the years is that if you shorten the barrel of your rifle or hunt with a carbine that you are going to drop so much velocity.
www.guns.com
That would be a lot of time and money for sure.
From the article and Phil Sharpe's results:The Myth of Barrel Length and Velocity Loss :: Guns.com
One of the biggest myths that I have heard over the years is that if you shorten the barrel of your rifle or hunt with a carbine that you are going to drop so much velocity.
The myth at the time (and one I still hear) is that there is a rule of 25 fps lost for every inch of barrel taken away: Sharpe proved that wrong.
Sharpe proved that the average loss was really about 12 fps for every inch lost, hardly something to fret over.
He may have proved this with a 06 and the powders/bullets/barrel he had then, but shooting many different calibers (from 20 caliber to 338) and many chamberings from 14" to 18", my numbers would be higher. I can see getting less loss, once you get up to that 20" or 22" compared to 24"-28".
I tell people to guesstimate approx 25-35 fps per inch. I have found it to be less with some smaller cartridges, compared to larger Magnums.
Plus, I am not going for speed, I am going for accuracy, to where I can do sustained shooting.
Plus, if you take a new match barrel and start your testing, and you keep shortening your barrel, that barrel is going to be speeding up some (Throat breaking in) as it gets shorter. Also use a couple of different barrels (Button and Cut)
Show me data from a barrel that has 200 rounds down it's tube already, and they are going for 1/2 MOA to 1/3 MOA accuracy at each length and powder charge with a variety of bullets in the same weight, where you can do sustained shooting and not pressure up and you will have my attention.
I wish my shorty barrels (14-18 inches) only had 12 fps per inch loss compared to longer lengths (24-28 inches).
It would be nice to only have a 120 fps loss in a 16" versus a 26" barrel
Having said all of that, maybe my math skills just suck
Buttermilk
Well-Known Member
I had a 280 AI 16.5" barrel as well as a 15" barrel. Both of those barrels gained 150 FPS going from 4831 to 7828 powder.
My 7mm RSAUM 17.5" barrel will do 2800 FPS with H4831sc and Berger 169 VLD's. With H1000 and the same bullet it does 2850 FPS.
In my short barrels I've gained velocity with slower burning powders.
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