Home Forums Hunting & Shooting Hunting Rifles Velocity Gain of 280 Reamed to AI in 22 Inch Pipe

I'm not a fan of a 22 inch barrel on a 280 AI but am curious as to the velocity gain obtained when reaming a 280 Rem to 280 AI in a 22 inch pipe?

I am a fan of 22” barrels on hunting rifles to be carried in rough country. Warren Page’s “Old Betsy” had a 22” barrel and it was chambered for the 7mm Mashburn which is close to a 7/300Win. That said, I have had two different “improved” 280 Remington’s. One was an Ackley and the other an RCBS. Of the two I preferred the RCBS version. I was very interested in the velocity gain so started with new barrels, had reamers made, shot & chronographed both barrels before and after. I also had two other 280’s. Both had long throats for OAL’s of 3.48”. I was trying to maximize a light mountain “sheep rifle”.

I measured case head expansion to track pressures as it was the only way I had to attempt to be objective. I ran the loads over two different chronographs. I expended a lot of time and money. This is what I found.

Most of the velocity gains over the standard 280 were due to higher pressure and increased OAL of the ammo. At equal pressures, the difference was 35-40 fps. I didn’t mention that I started with 24” barrels and then cut both to 22”. The velocity loss with optimal loads either of the improved versions was about 22-25 fps per inch.

So, an improved 280 using optimized loads with 140’s in a 24” barrel will move around 3125, in a 22” the improved will go 3080, and in a standard 280 with a 22” barrel the 140’s move along at 3050. There is some variation in barrels so to minimize that I got three of the barrels from a maker of cut rifled barrels all of which were made sequentially. The barrel maker made test barrels for commercial laboratories and NASA.

I was using 98 Mauser actions and the improved cartridges never cycled from the magazines as well as the standard 280. I had the best metalsmiths in the country try to make them work. There isn’t anyone who can make an improved function as well as the standard 280 using a 98 type action. This isn’t because of the sharper shoulder but because of the lack of taper in the case body.

I had been reading and was convinced that a 280 was slightly better than either a 270 or a 30/06. I loaded ammo for a buddy who had a 270. It wasn’t a big deal to get his 130’s up to 3100 fps in a 22” barrel. Eventually I sold all the 280’s both standard and improved in favor of the 270. About that time I started doing much more hunting and have used a rifle chambered for the old 270 for many many trips. I sold all my 7 and 30 magnums. Today all I use it a 270 and a 375.

If you must have a 280 then increase the throat to 3.48”. The 22” barrel is noticeably more agile to handle and carry.

Wow, you took that task seriously! Thanks for the info. Just curious on the 270, did you twist it faster than 1/10. I ask because I have two of them and they are both .5 MOA guns with 130's but with 150's not so much.

Holy [bleep] RinB. That’s an impressive bit of information.
Thanks for taking the time ...

This has to be one of the most informed and impressive posts I've read since I started internet hunting in 2001.

Thank you for that info. I have a 22" .280 and have thought about getting it reamed to AI. Haven't done it, mostly because I have a 7mm RM and enjoy the .280's mild recoil. It does what I want and will likely stay unchanged as long as I own it. Why mess with a good thing?

Very interesting test.

Did you consider NOT increasing the throat, increasing twist, and increasing bullet weight?

The 270 ain’t so gay after all!!!!

JMC,
I fooled around with different twists in the 280 and the 270.

In the 280, 1-9.5, 1-9. I used 140 and 160 bullets. Initially I thought the 160’s would be better but found the 140’s preferable. In the 270, 1-10, 1-9, and 1-8. I also tried different bore diameters.

Most of this didn’t make any objectively observable difference. I do believe faster twists tend to expand a bullet to a very slightly larger diameter. Here I am talking about monolithic or bonded core bullets.

I have been using a 1-9 twist in my .270’s with an OAL of around 3.48”.

At the same time I was doing similar experiments with the 300Win and decided that it didn’t work much better than a 270. I had several but have sent them to live elsewhere. I have fiddled with many cartridges and decided they are a waste of time if you are interested in hunting.

I began trying to build the optimal mountain rifle and found that I couldn’t improve on the 270 especially when used with modern hunting bullets. A 270 with 130 TTSX will penetrate around 34” of eland meat and bones.

All of my expensive experiments convinced me that there really isn’t much to learn. Go to a 9.3 or a 375 to get to a meaningful difference.

I spent the cost of a pretty nice sports car to learn that there isn’t much to learn. It would have been wiser to spend the time and money practicing and going.

So then what you're saying is that the answer is the 270Ai...?

Did I get that right?

Boog,
Surely you jest! Go back and carefully read my first comments.

RinB, I’ve been here a long time, don’t post much. That’s about the best post I’ve seen on here. Thank you.

JBab,
Thank you, sincerely.
I am always happy to pass along that which I have learned.

Great Post Uncle Rin- I've only had one .280 AI and that was in a 22" Mountain rifle reamed out. I was dealing with R22 then and a finick barrel. The loads it liked ( 150NBT/61gr R22 and 160HC/7828 ( don't remember the charge now, 25 yrs later) were 150/2950 and 160/2800. I only beat my standard 280 loads by 50 fps. It was still alot of fun, but I learned alot from that. Another Ackley Improved I never seemed to get much out of is the 30-06 Improved. My 35 Whelen AI had the stock "Classic 22" factory barrel", but the loads it liked were, come to find out from QuickLoad data, 20 yrs later, all ran in the 72-74K range, ha. I moved on. Now I like my 24" .270Win and 24" 300WM. They scratch all my itches...:)

Excellent work and post.

Better you than me!

RinB thanks for your post and research. I purchased a Rem 700 MR 280 a couple years ago. Before I purchased it, I researched the AI version and decided I didn't need it. My 280 pushes a
150 NBT at 2950.

Deans

Deans,
Your 280 loaded with 150’s is in the group of the very finest of all time. I have used the 150 Swift Scirocco’s and they are great. The 140 TTSX is another great one.

If the 280 was readily available worldwide, I would still be using one. However it isn’t. I abandoned the 280 in favor of the 270 because on one trip I didn’t have time to load ammo and thought I could buy some. I drove across south Idaho and Wyoming stopping in every town looking for 1 box of any 280 ammo and couldn’t find a single box. I would have settled for 5 rounds. Nada.

I used the 280 on around 75 head of plains game. After using the 270 on many more, I can say there isn’t any difference between the 270 & 280. Also, I have used the 7Rem and 300Win. The magnums recoil more and make shot placement more difficult. In what counts they aren’t objectively better.

Regards,
R

J K,
I fiddled with 2 338-06’s and 2 338-06 AI’s. The total “gain” was maybe 25-30 fps; note that is total gain not per inch. Waste of time and resources. Lots of guys want to be different. I suggested getting a tattoo on their forehead saying “DIFFERENT”. Last time I got a lot of grief for my suggestion.

Best to you,
R

Yes...of course...just kidding...

I'm not as clever as some here but I do try my hand at levity from time to time

However, I am in complete agreement with your conclusions.

I put tubes on several rifles for a fellow who finds Elk in places where long range opportunities are frequent, and often the only ones presented. Being a meticulous shooter, and having gone through the gamut of 300, 338 blasters, he found the 270 WSM to be equally effective at extended range with the right bullet with a LOT less blast and shoulder banging. That's since changed somewhat since Matrix got out of 270 business.

The 280 is about as good as it's going to get on the '06 case. I decided long ago that, for the money, the best way to improve any round is to put a better bullet on top.

For a cost of about 2 quarters one can often achieve as much as 50% greater downrange velocity / energy...and what a wealth of bullets are available for the 7mm bore...2nd only to 30 cal.

If one shoots far enough to need it, that is..

I'm still trying to wear out the barrels on the 30s I have.

There was a thread where such a comment would have gotten you called a member of the lace panties brigade. The suggestion was for a new hunter to start out with a 300 mag.