Piercision Rifles 260AI Build

Piercision Rifles

Lil-Rokslider
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Feb 14, 2023
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Well after building several shorter barrel 6.5 cal magnums for myself I decided that a 260AI would probably do the same thing since its not overbore. The prc's and saum's lose quite a bit in the shorter barrels. I decided to put a 20" barrel on it since Im running a can. Unknown Reaper only added 5 3/4" past the crown. The hydro formed brass hammered while breaking the barrel in. Consistently half moa or better at 625 yds. Since I had over 10k of the 140 elite hunters on the shelf I decided I might as use em up lol. I have a pile of N555 so I tested it first after the barrel was broke in and brass was shot once. 46.2-47.0 was under 2" tall on the ladder test at 625 yds. 140 Elite Hunter at 2790 fps. There was another node up at 2865 fps but it wasn't as wide and had some powder crunch while using a drop tube. No pressure signs at 2865 fps. Decided to just load up in the middle of the mild and wide node. Shot 4 groups in a row with 46.6 gr at 625 yds and all had under 2" of vertical. Since then Ive shot a bunch more groups at 625 yds and all have been under .5 moa vertical. Same w 900 yds. Ive shot some 1-2" groups at 900 for 3 shots and several 3" groups. And a 5 shot at 900 that was 2.75" tall and 3 1/2" wide. This thing is stupid accurate and consistent as well as hardly any recoil. I don't see the Alpha small primer brass wearing out in less than 25-30 firings due to this mild load. Case head isn't moving after several firings. Ill be using this rifle for everything that doesn't require my 300 norma improved. Cow elk out to 600 and deer/antelope to 1000.
As a side note I did try H4350 and it had some nodes at 2830 and 2850 but they werent near as accurate as this n555 load. And the 4350 loads showed a little more pressure on the case head.

Rifle has the following:https://www.facebook.com/DefianceMa...Z93QWUkAktmCfIguV7sMVA50bs6PdtAw&__tn__=-]K-R
Defiance ANTIX Short action cut for unknown 3.150 mags and ignition gone through
Manners Pro Hunter Adjustable
Benchmark 6.5 cal 7.5 tw 20" sendero light
Unknown Bottom metal and 3.150 mags
Triggertech Rough Diamond set at 1.5 lbs
Unknown Reaper with the SRS mini CB
Nightforce NX8 4-32 MIL C bedded into some NF 4 screw rings
Rifle with optics and suppressor weighs 9 lbs 4 oz.
As soon as the NX6 5-30 MIL comes in Ill throw it on and try it out.
Ill be building some of these to have in stock shortly.
Dies are readily available from Redding or Short Action Customs
Alpha Brass and 140 Bergers are on hand.

Rifle with optics and suppressor weighs 9 lbs 4 oz.
As soon as the NX6 5-30 MIL comes in Ill throw it on and try it out.
Ill be building some of these to have in stock shortly.
Dies are readily available from Redding or Short Action Customs
Alpha Brass and 140 Bergers are on hand.

www.piercisionrifles.com
rifle.jpgbedding.jpg5@100.jpg3@625 group 2 - Copy.jpg3@625 group 3 - Copy.jpg3@625 group 4 - Copy.jpg3@625.jpg3@900 pic2.jpg3@900.jpg900 yd 5 shot pic 3.jpg
 
Ryan,
Great looking build!!!

Took a bunch of parts to my local gunsmith bud and he just punched out a 260 barrel to AI for me, gonna start fire forming soon. Barrel already had over 100 rounds on it so gonna form 100 and might take it for elks this fall...
 
Very nice gun and load you have there. I'm a big fan of the standard 260 Rem, how much more speed does the 260 AI get over it on average?
Most say 100 fps or so. On all my improved cartridges Ive done Ive generally settled on a mild and wide node. Mild nodes are generally alot wider than the top nodes. The mild node generally ends up being a higher node in the original case. This node Im at is no exception. .8 gr wide on the ladder test was under 2" tall at 625 yds. And the velocity was almost the same. .6 gr spread was single digit spread. My mild 300 Norma improved load is like a grain wide also. Those super wide nodes will stay in tune day in and day out. The brass on the improved hardly grows after the first firing. You could go quite a few firings before you had to trim it. Same w my 300 nmi. After the first firing the 300 nmi brass grew .005 in the next 4 firings. From firings 6-15 it only grew .005 or so on the piece I tested. This 260ai brass is looking to be the same. If not even less growth.
 
260ai is such a slick round. I I’ve had one for a few years, yours is definitely faster than mine. I’m shooting the 147s at 2890fps with a mild load, out of a 26”. I could get some more speed with other powders, but I found a sweet load with h4831sc so settled on it.


(It’s for sale if anyone’s interested..)


Sent from my iPhone using Tapatalk
 
Most say 100 fps or so. On all my improved cartridges Ive done Ive generally settled on a mild and wide node. Mild nodes are generally alot wider than the top nodes. The mild node generally ends up being a higher node in the original case. This node Im at is no exception. .8 gr wide on the ladder test was under 2" tall at 625 yds. And the velocity was almost the same. .6 gr spread was single digit spread. My mild 300 Norma improved load is like a grain wide also. Those super wide nodes will stay in tune day in and day out. The brass on the improved hardly grows after the first firing. You could go quite a few firings before you had to trim it. Same w my 300 nmi. After the first firing the 300 nmi brass grew .005 in the next 4 firings. From firings 6-15 it only grew .005 or so on the piece I tested. This 260ai brass is looking to be the same. If not even less growth.
Thanks for the info, much appreciated. I always thought the 260 AI was an awesome cartridge.
 
260ai is such a slick round. I I’ve had one for a few years, yours is definitely faster than mine. I’m shooting the 147s at 2890fps with a mild load, out of a 26”. I could get some more speed with other powders, but I found a sweet load with h4831sc so settled on it.


(It’s for sale if anyone’s interested..)


Sent from my iPhone using Tapatalk
I have some different dimensions on my freebore as well as it being very long. But Ive also always gotten pretty good velocity out of N555. THE ES and SD has always been phenomenal with it as well. Its not a crazy speed powder like n560 or rl26.
 
the 260AI is a cool case. Its downfall is fireforming brass. I would guess the best way to remedy that would be to have the gunsmith cut a section of barrel drop with a minimum dimension chamber and buy 500-1k pieces of quality brass and the cheapest bullet you can find for loading . Otherwise you cut into your barrel life fireforming your brass
 
the 260AI is a cool case. Its downfall is fireforming brass. I would guess the best way to remedy that would be to have the gunsmith cut a section of barrel drop with a minimum dimension chamber and buy 500-1k pieces of quality brass and the cheapest bullet you can find for loading . Otherwise you cut into your barrel life fireforming your brass
I had the brass hydro formed before I shot it. All the first firing did was sharpen the shoulders a little. Ill have hydro formed brass available for anyone buying a rifle from me.
 
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