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My first "wildcat": 6.5-280ai

shanejohnson2002

Drill Sergeant (no.... really)
Full Member
Minuteman
Jul 5, 2012
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Does anyone have experience with this cartridge? It seems like an easy way to get to (what is basically) a 6.5-06AI.... within a few thousandths and a grain or two or capacity. Since 280ai factory brass is available, it seems easier than bumping or fireforming .30-06, .25-06 or .270 brass.

I've already got a barrel maker willing to chamber for it if I provide dummy rounds (Preferred Barrel Blanks). I'll be using West Texas Ordnance's plan of necking down 280ai in a single pass through a .292 bushing die (which I already have for 280ai), then seating with my 6.5mm seater. I'm anticipating not having to trim much, mostly just deburr / chamfer.

I'm thinking 140 or 144 Bergers over 55gr of H4831sc and Fed 210m primers would be a good safe start to work up from. Max for 280ai is listed as 60.5gr for 150gr, and 62.5 for 140gr in the Nosler online data. If that sounds wrong/ crazy, please let me know.
 
So I went for it. Here's the evidence.

6.5-280ai with a 144gr Berger LR Hybrid on the left, factory Hornady 6.5 Creedmoor 147 ELD-M on the right. The process so far has been super smooth. The only hiccup so far has been the fact that my 3-way cutter/deburr/chamfer tool is leaving a slight burr around the outside of the case mouth. I re-adjusted it and drove on.

Trimming and COAL I just held to standard 280ai...2.515" for case length, 3.33" for COAL. That gives a CBTO of 2.644". Since these are dummy rounds for having a chamber made, I'll just try to repeat this CBTO.

Outside neck diameter is .293, I have a .292 bushing installed. I'll probably drop down to a .290 to make my final run of 3 dummy rounds.
101580785_383875489237267_916597199796699136_n.jpg
 
I’d look into 6.5 saum loads
Case capris almost identical.
I’d look into R26, h1000 and 7977 powders
H4831 is a fantastic powder but you might not get full speed before pressure.

I was looking at 6.5-06 loads and extrapolating from that, but always subtracting a couple of grains to start at a safe pressure. I considered 6.5 SAUM but decided I wanted a standard bolt face. If the capacities are that close, I'll definitely use the data. Do you have any numbers for case capacity? 6 5-06 AI is 64ish gr / H2O capacity, quickload shows 60.6 grains RL26 as a max load for 140gr Nosler bullets. To get my safe starting load, I subtracted 5 grains. I'll work up .5 gr increments until I see some pressure signs, then back down a bit a d shoot a ladder based off of that number.

I'm pretty excited to try some of the new Berger 153.5 gr LR hybrid and 156gr EOL...but this should be a laser with 140 hybrids / elite hunters.

I have 1lb of RL26, and both standard and magnum FGMM primers.
 
I was looking at 6.5-06 loads and extrapolating from that, but always subtracting a couple of grains to start at a safe pressure. I considered 6.5 SAUM but decided I wanted a standard bolt face. If the capacities are that close, I'll definitely use the data. Do you have any numbers for case capacity? 6 5-06 AI is 64ish gr / H2O capacity, quickload shows 60.6 grains RL26 as a max load for 140gr Nosler bullets. To get my safe starting load, I subtracted 5 grains. I'll work up .5 gr increments until I see some pressure signs, then back down a bit a d shoot a ladder based off of that number.

I'm pretty excited to try some of the new Berger 153.5 gr LR hybrid and 156gr EOL...but this should be a laser with 140 hybrids / elite hunters.

I have 1lb of RL26, and both standard and magnum FGMM primers.
I prefer standard primers for that amount of powder.

I actually use 60.6 right now in my 7 saum for 190’s.

Case capacity is approximately 68-70
 
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I am shooting a 6.5/06 and I think I have been loading it too hot when we got a Labradar on it. I had no idea as to how fast it was going.
I am using RL23 and have dropped from 52 gr. to 49 and am still over 3000. gonna drop some more. I want this barrel to last for a while.
 
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I am shooting a 6.5/06 and I think I have been loading it too hot when we got a Labradar on it. I had no idea as to how fast it was going.
I am using RL23 and have dropped from 52 gr. to 49 and am still over 3000. gonna drop some more. I want this barrel to last for a while.

Less powder with good velocity would be awesome. I already have 6.5 Creedmoor in both short and long barrels, so basically I'm covering 2200 - 2800 fps... but the idea of sending a 140-155 grain bullet at 3k+ fps is tempting to say the least. 5 mils at 1k would be amazing.

I'll give RL23 a try as well... I'm pretty sure I've seen 6.5-06 data out there for it.
 
I looked high and low for RL23 data and didn't find shit. I even called Alliant with no luck.
It does shoot flat compared to my Creedmoor. I like it.
 
I’m sure you’ll enjoy the round! You’re pretty close in case capacity to the 6.5 Sherman, just a smidge less. For what it’s worth, I’ve been able to sling the 140 VLDs over 3200 with RL-26 out of my 6.5 Sherman. Will be trying out the 147 ELDM with RL-26 here shortly.
D5E6C816-9195-4960-A850-FF05CF2EF1A5.jpeg
 
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Should also add- Peterson just released 280 AI brass. Should be excellent for this application.
Another source of brass would be great. Hornady 280ai brass (which is what I have) seems to get mixed reviews, but the Norma brass is significantly more expensive.

I wish Starline and Alpha would get with the program
 
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No announcement that I saw, but Eurooptic.com had some in stock a few days ago. They were out of stock By the time I saw, but still had plenty of 280 Rem and 270 Win left. Snagged a box of 270 to use in my 6.5 Sherman.

So, something I'm not clear on....what's the forming process for a 6.5 Sherman? Is it fireforming/hydraulic, or just a pass or two through some dies? Just curious more than anything. I'm mostly unfamiliar with it, other than knowing it's 30-06ish-based and exists.
 
So, something I'm not clear on....what's the forming process for a 6.5 Sherman? Is it fireforming/hydraulic, or just a pass or two through some dies? Just curious more than anything. I'm mostly unfamiliar with it, other than knowing it's 30-06ish-based and exists.

Forming 6.5 Sherman brass isn’t too hard - although it requires more work than a 6.5-06 Ackley Improved, as the shoulder is moved forward quite a bit. Basically, start with either 270 Win or 280 Rem brass. Neck down to .264 to create a false shoulder to headspace off of. You want a nice crush fit when you chamber the round. Fire and out pops Sherman brass. You can form with hydraulic dies, but can be messy and still leaves a rounded shoulder. I’ve found my fire forming rounds to be plenty accurate as well.

Here’s a photo showing a case ready to be fireformed next to a formed case.

92C5D1D8-2BD7-489B-89F5-DFD1F867DD88.jpeg
 
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Forming 6.5 Sherman brass isn’t too hard - although it requires more work than a 6.5-06 Ackley Improved, as the shoulder is moved forward quite a bit. Basically, start with either 270 Win or 280 Rem brass. Neck down to .264 to create a false shoulder to headspace off of. You want a nice crush fit when you chamber the round. Fire and out pops Sherman brass. You can form with hydraulic dies, but can be messy and still leaves a rounded shoulder. I’ve found my fire forming rounds to be plenty accurate as well.

Here’s a photo showing a case ready to be fireformed next to a formed case.

View attachment 7342766

That's quite a difference. Pretty cool.
 
I prefer standard primers for that amount of powder.

I actually use 60.6 right now in my 7 saum for 190’s.

Case capacity is approximately 68-70
Agreed, the exception being N560, which needs a Mag primer in this case
 
I’d look into 6.5 saum loads
Case capacity almost identical.
I’d look into R26, h1000 and 7977 powders
H4831 is a fantastic powder but you might not get full speed before pressure.
N165 is another good powder in this case. Advantage is the lowest temp of combustion keeps the barrel cool and might give longer life. Accuracy is there. Burns clean. Relatively temp-stable single base. Disadvantage is some loss of MV compared to others
 
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