20” 7mm CF Barrel Recommendations

Mark37082

Well-Known Member
Joined
Sep 30, 2021
Messages
2,884
Location
Tennessee
I've been thinking (not clearly) that I need to add a shorter barrel to go suppressed on a planned build. I have 24" Proof Sendero sitting at the GS waiting on the Anti X receiver. I put a Ultra 7 suppressor in jail and started thinking and reading on minimal FPS penalties going with 20" barrel. This rifle will be chambered in 280ai. I am wanting to keep a Sendero contour as I already have the stock for this contour. I just am struggling with the thought of having 30+" of barrel hanging on every vine and branch while hunting. It seems 20" options are not as prolific on CF barrels in this contour. Any thoughts or suggestions? I can consult my GS, but would like to be armed with knowledge before this discussion.
 
I'm building a 20" 7 saum with a sendero contour as we speak. Using a anti action too. My barrel is a muller works carbon fiber.

Just out of curiosity why do you want to go with 280ai vs another caliber that would perform better with a short barrel such as a 7 saum or 7SS. Typically short fat cases perform better in short barrels because the powder burns faster vs a long skinny case.
 
Last edited:
Yeah I'll second the short mag part, I'd go 7 wsm over the 280 ai but since you have the standard bolt face then just go with it.
Definitely don't go over 20" with a suppressor, I have a 24" barrel on one of my rifles and it's way too long to hunt with using a can.
Also you won't save much if any weight using cf at 20"
 
I have a 20" 6.5SS, and to be honest, I kind of regret the huge sacrifice in velocity.
I just finished a 20" 7SAUM. Final load is a 169 HH at 2787fps. In comparison, my 24" 7SS is pushing a 184 Hyb @ 2838fps. 15gr heavier bullet at 50fps higher velocity, and much better BC. I can push a 175 @ 2900+, and a 165 TMK @ 2975 pretty easily.

Here is another direct comparison. I have a buddy who's daughter shoots a 26" .280AI, 175 Elite at 2925fps. He built a 22" .280AI for himself. Exact same ammo only gets 2805fps. For 4" of barrel length, he loses 120fps, or 30fps per 1".

If you are hunting out to 600-700 yards, I think a 20" works OK. But start stretching it out, and you run out of HP too early with the short barrel speed losses.

To me, a short barrel rifle is perfect for a lightweight backpack rifle that will see shots out to 500-600 yards. Beyond that, give me a longer barrel and more speed.
 
Lance summed it up pretty dang well as usual!

I guess it really depends on your style of hunting, your terrain, and yardage for your shots. Most of my rifles are 24"-26" but they were mostly built before the short barrel suppressor craze that's going on now and wanting maximum FPS in a hunting rifle. I do have suppressors that range from 6.25" to 10.4" so that's makes a 26" barrel pretty long.

I'd run the numbers for your yardage you want to shoot and see what barrel length you'd need to stay above 1,800fps or so (run wind drift too) and if the compromise is worth it to you. You can compromise some with a 22" or 23" barrel as well. I have a 7WSM with a 26" barrel that I really like the speed of with a 180 grn Berger @3030fps suppressed. Been debating having it cut down to 22" or 23" but still up in the air.

I have a hip suppressor pouch from Armageddon Gear that I can carry suppressor off the rifle and thread the suppressor on for a shot since I primarily glass something up first then get ready for the shot. If you're dialing you have time to throw the suppressor on. It can still be shot w/o a suppressor off hand and at that distance poi shift won't mater enough to be outside Minute of deer. My poi shift at 100 yards is around 1" to 1.5" depending on suppressor weight/length, and my barrel contour.
 
Last edited:
I really appreciate the input. My typical hunting can range from near point blank range in dark woods to 500+ yds in clear cuts. Longest shot in my life was 1100 at a coyote that was in perfect conditions and was absolutely not typical. I have never hunted with a suppressor, but like the idea.
In the end, I wanted the 280 AI to give me a relatively light weight rifle that performed well, was efficient, and filled a gap using my supply of .284 pills. Ive wanted a suppressor for a long time, but purchased all the build components without considering hunting suppressed. I was thinking about keeping the 24" and adding the shorter barrel in a switch barrel configuration.
I like the idea of carrying the suppressor and spinning it on once I am in position for a sit. If I can predetermined the POI shift and make the adjustment in the field, it may be an option.
 
Another option to keep in mind is the 277 fury will be out eventually. 2900 fps out of a 16" barrel. With a 20" barrel possibly over 3000 with a 150g bullet even more with a lighter one. I would keep going the route you are going with the 280 and 24" and pick up a cross in 308 until the fury comes out then it's just a barrel swap. I like my cross other Tha the 2 stage trigger but I would imagine there will be aftermarket eventually. Just one more thing to think about.
 
I've been thinking (not clearly) that I need to add a shorter barrel to go suppressed on a planned build. I have 24" Proof Sendero sitting at the GS waiting on the Anti X receiver. I put a Ultra 7 suppressor in jail and started thinking and reading on minimal FPS penalties going with 20" barrel. This rifle will be chambered in 280ai. I am wanting to keep a Sendero contour as I already have the stock for this contour. I just am struggling with the thought of having 30+" of barrel hanging on every vine and branch while hunting. It seems 20" options are not as prolific on CF barrels in this contour. Any thoughts or suggestions? I can consult my GS, but would like to be armed with knowledge before this discussion.
It all depends on what YOU want, and the game and Max distances you will be hunting at. You should be looking for a performance level...Whatever performance level that would be, should be the determining factor for cartridge and barrel length.
You can do a lot with a shorty.
As mentioned earlier, if you really want to stretch things out with a shorter barrel, go to a bigger cartridge to reach your impact velocity goals with said chosen hunting bullet.

17" 280AI with factory Nosler ammo with the 140 AB: MV is 2961 fps
R06ndFxl.jpg

Newbie shooting it last fall.
 
I have a X-Caliber 20" CF 280ai barrel. I have 2 loads worked up 172AH at 2876 and 162 ELD-X at 2878. I lost about 100ish fps vs what I got with my 23" 280ai. I much prefer the shorter barrel.
 

Attachments

  • IMG_1514.jpg
    IMG_1514.jpg
    533.3 KB · Views: 42
I'm not sure of the brass situation but you might also consider 284 win. I've never seen a real barrel cut down test for 284, 280 AI, or 7 wsm but it does seem like longer cases with thinner powder columns do fair a little worse. A 284 with a 150-168 might give you everything you want. The Sierra manual only shows 280 AI having about a 100 ft/sec advantage over 284 in that weight range and that's at 2.800 COAL for the 284. Plus 284 is just cool and you should do it for that reason alone
 
My 18 inch center grip XP, chambered in 284 Winchester with a 162 grain bullet has a muzzle velocity of 2600 ft./s.

My 17" center grip XP, chambered in 280AI with factory Nosler ammo with the 140 AB: MV is 2961 fps

With a 20 inch 280 Ackley improved, you can kill a long ways out there, if you are on your game when shooting on demand from a field position
 
My 18 inch center grip XP, chambered in 284 Winchester with a 162 grain bullet has a muzzle velocity of 2600 ft./s.

My 17" center grip XP, chambered in 280AI with factory Nosler ammo with the 140 AB: MV is 2961 fps

With a 20 inch 280 Ackley improved, you can kill a long ways out there, if you are on your game when shooting on demand from a field position
Is the 284 loaded to 2.8? Also noticed you are talking 2 different bullet weights. All things being equal a 284 loaded to whatever pressure you are currently loaded to would be right at 2800 ft/sec with a 140.
 
I'm going to disagree somewhat with the statements about reduced velocity being super limiting at long range.

For example my 18" 7-300 wsm LRI is sending the 175 eldx 2800 fps, at my elevation of 3500' that gets me to 900 yards with an impact velocity of 1800 fps.
If I ran a 26" barrel and sent them 200 fps faster that'd extend the range by 150 yards to 1050.
If someone is hunting elk in open country where shots are expected to be 1000 + then yeah a suppressor/short barrel doesn't make much sense.

I think what most people are realizing though is that short light suppressed rifles offer a lot of advantages over long barreled braked rifles with deafening blast.
And that they can be just as effective for 95% of the practical shot opportunities that one will encounter in the west.
 
My 18 inch center grip XP, chambered in 284 Winchester with a 162 grain bullet has a muzzle velocity of 2600 ft./s.

My 17" center grip XP, chambered in 280AI with factory Nosler ammo with the 140 AB: MV is 2961 fps

With a 20 inch 280 Ackley improved, you can kill a long ways out there, if you are on your game when shooting on demand from a field position
That is impressive with a 17" barrel. This is a project rifle where wait time on the receiver is giving me too much time to think about things. On one hand it is giving me enough time to order components (dies, brass, etc.), but it is also adding a little pain in the wallet. The good news is I have other options to shoot in the meantime. I'm stuck with the receiver (paid for) ,barrel and stock (in hand). Dies have been ordered and brass is sitting in the reloading room.
 
Top