280 AI Barrel Length for Suppressor

[Joelweb]

I'm sure there will be different opinions on this, and I'd like to hear them. I've got a Kimber Mountain Ascent in 280 Ackley that I've had for nearly a decade. I love this gun--it is a pile driver and shoots great with handloads. I hate to mess with it, but I'm fed up with the earplug scramble and ordered a Banish Backcountry suppressor. Kimber makes an adapter that will make it fit.

I'm going to get the barrel shortened. It is presently at 24". I'm leery about cutting too much given the standard case size and am leaning toward 22", although I'm also considering 21".

Anyone here have real world experience cutting down a 280AI? How short and what are you seeing for velocity changes? Thanks in advance.

 

[MThuntr]

Knowing those are pretty thin barrels I'm not sure how far you'd have to chop for the right thread diameter but your gunsmith will be able to help you with that. I don't know if you'd notice much of a loss by going to 20 or 21 and adding a suppressor. You could be out 100-150fps but possibly gain back 40-50 with a suppressor (that's a guess based on sample of 1 for adding suppressor to a 20" barreled rifle)

 

[BrBa]

Velocity loss is going to vary based on your powder and bullet weights. If you use faster burning powders it may reduce your delta to some extent. 2 inches less doesn't seem like a lot, but adding the weight of an adaptor and suppressor on the end of a thin barrel is going to change the harmonics. I went thru a similar exercise with another rifle and decided to go with a rebarrel with heavier contour.

 

[HGL]

My .280 Ackley wears a 22" Brux with a Tbac 7.

My velocities with RL-26 are below. Granted, 26 gets some good speeds in the .280 but its almost impossible to find these days, got a couple pound stash for hunting loads.

168 VLD @ 2875
162 ELDx @ 2950
160 AB @ 3000

I'd be fine with any of the above loads running 50 fps slower from a 20" tube. My gun loves H4831sc too, but its a good bit slower in the velocity department, ymmv.

 

[2Stamp]

My 280ai CA Ridgeline with a 22", and a SiCo Omega, gets 3080 with barnes 145 LRX and H4831sc. I didn't push the reloading on this to see how fast it'll go, just book max. I have no idea it that's average or not.

I haven't messed with heavier bullets yet though.

 

[pods8 (Rugged Stitching)]

My 280ai CA Ridgeline with a 22", and a SiCo Omega, gets 3080 with barnes 145 LRX and H4831sc. I didn't push the reloading on this to see how fast it'll go, just book max. I have no idea it that's average or not.

I haven't messed with heavier bullets yet though.

I don't think you have much to push there imho, I'm at 3130fps with the 145LRX using IMR7828SSC in a 24" barrel and its a load that is hard on primer pockets but this is with fire formed Rem brass (set it up before other brands besides nosler were making brass) so better brass might hold longer. What brass are you using and how are your pockets holding up?

For the OP thats showing 25fps/in dropping from 24" to 22" with a similar stout load.

 

[2Stamp]

I don't think you have much to push there imho, I'm at 3130fps with the 145LRX using IMR7828SSC in a 24" barrel and its a load that is hard on primer pockets but this is with fire formed Rem brass (set it up before other brands besides nosler were making brass) so better brass might hold longer. What brass are you using and how are your pockets holding up?

For the OP thats showing 25fps/in dropping from 24" to 22" with a similar stout load.

Good to know. To be fair, I really don't have a need to push it harder.
I'm using a mix of Nosler brass and formed Norma. Pockets have been good, no issues.

 

[passinggas33]

I have a 280AI in both a 24” (custom) and a 22” (kimber Mtn ascent). My gunsmith felt that going much shorter than 22” because of the flutes might start to impact the harmonics of the barrel and potentially lose accuracy. Super happy with that one at 22”. IF I were to do my custom all over again, I would have a 20” barrel on it with a permanent suppressor. The speed difference between MY two hand loads is only about 20 fps so not that big of a deal.

 

[Joelweb]

Appreciate it, everyone.

 

[Unckebob]

I had my 24" barrel cut to 20" because I wanted to use my suppressor.

Using the same box of factor ammo using the 140g Nosler BT. I lost 100fps.

I am glad I went with the 20" barrel.

 

[Unckebob]

I took my 20" 280AI out to test my new Garmin chrono today.

To test how must velocity I was leaving on the table, I shot a few rounds of Hornady Prevision Hunter @62g. The box said the velocity was 2850 in their 24" test barrel. I got 2710.

I was getting just under 3000fps with the 145 LRX that I hand loaded.

 

[bigunit]

Mine has a 22" carbon barrel.
It's favorite loads so far are:
Sierra 165 tgk @2925 h4831
Hornady 162 eldm @2880 w h4831
Hornady 180 eldm @ 2825 w 7828ssc

 

[Krumfola]

This was helpful info. I’m starting my build and I think I’ll go 22” to be run with a TBAC Ultra 7. Planning on 162gr ELDX factory stuff and don’t wanna risk dropping below 2700fps with a 20” barrel.

Having a hard time choosing a stock at the moment.