280AI Long Range Build.

L.Parratt

L.Parratt

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Location
Edmonton Alberta.
Figured id share this here since its somewhat close to being done

The concept of this rifle is a Affordable to shoot, accurate 1 Mile ~ Rifle.

I settled on 280AI as its a non magnum Cartidge but with plenty of performance behind it.

Here's the details of the rifle so far

Action : True/Blueprinted R700 LA
Barrel : KS Arms 35" 1.25 Cylinder.
Chassis : MDT ACC Elite
Stock : MDT SCS
Trigger :Trigger Tech Special Flat
Scope Rail : MDT 20MOA
Scope : Bushnell Match Pro ED 5-30 + Sphur
Bipod : MDT Gen 2 Cyke Pod double.

Will be adding chassis weights and 3D Printed "Night vision bridge"

Total weight is planned to be 35lbs~

Top gun theory would predict accuracy to .6MOA groups.

Left to do still
Its done!!!
20260214_102808.jpg
 
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Did something similar way back when. I called my version the 7 Mystic and it shot very well for me.

Things to consider... With a barrel that heavy, action flex will be a real thing and degrade performance. If you have to use a barrel that long, consider a barrel block or at a min, support the barrel with proper bedding. for what you want, there really isn't any advantage beyond 30" with 26" being more then enough and far easier to set up/tune.

Will you get the velocity you are hoping for? I doubt it. That case is still pretty small for bullets that heavy and ultimately, speed doesn't equate to accuracy (if you have quickloads, that can offer some great insight into possible outcomes). If you want to see what real world results are, just look at all the F Open shooters running 284s... 30 to 32" barrels in general. 180 to 184gr type bullets. Just over 2800fps was all the rage for a while with some trying to push towards 2900fps. It took a long time but the trend brought back speeds towards 2700fps as tuning was a pain as was wear.

Nowadays, the 7mm-6.5 PRC is popular. Substantially, more case volume BUT speeds are still the same (big drop in operating pressures which lead to excellent accuracy with stable tuning). Long match bullets have a sweet spot for rpm and speed so trying to push beyond that rarely, leads to best results.

wrt to 1 mile, any of the 162 to 180gr bullets will make the trip without much fuss.

FYI, I do alot of ELR shooting. 1mile with a 6.5 CM is simple. I run a 308win out to 2600yds with 2200/2300yds straightforward. You can compare the economics but the 308win setup with modern 200gr bullets aka FTR, can be super accurate and go a very long ways. Component costs may be less too if shooting in larger volume... for sure, barrel life will be substantially higher

Good luck

Jerry
 
280A1 N560.PNG280Ai R26.PNG

Heres two GRT Predictions ill be trying out once the rifles ready for the range (and barrel has sped up) GRT for me tends to be on the slow side on predictions. but well see what happens when its ready in a few more weeks here!
 
I don't have the 280 AI. I have the 7RM and the 7 WSM with the 160gr I can reach about 3000 fs however at 2900 the accuracy is best. Pushing to 3000 gains nothing and makes short work of brass. At 3000 your reaching max pressure. With the 280+ you match the 7 mags.
 
Hopefully it works out for you, but I don’t think you will get anywhere close to that velocity.
I have a 27” barrel shooting 168 vld loaded long(single feeding) 2930 fps
 
Rifle should be ready this month. I caused a delay by getting my Action Cerakoted.

Played around with GRT some more and the Warner 151gr 7mm Solid. In theory this might be able to sling them at 3400 FPS according to the simulation. Will that happen? Probably not haha. However they do list a 7mm Rem Mag for load data in a 26" Barrel will sling the 151 at 3167 fps.

Got 500ct of the LRHT and 50ct of Peterson ready to go. Gonna take 3 range trip or more to get the barrel speed up haha

Compared Theoretical Ballistics to my friends 300PRC 26"
 

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