At the end of the day, it boils down to what numbers are acceptable to OP.
What is to one of us may not be for the rest. Opinions will indeed vary on whether the sacrifices are worth the expense.
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So if one compares 6.5 Creedmoor vs 7.62 NATO in a 16” gas gun, what are the differences in:
1. Actual ballistic performance
2. Barrel life
3. Overall costs, namely per round
I can see 6.5 Creedmoor on 20-26” bolt and gas guns any day of the week over 7.62x51. For 16”, I question the advantage until I see better data. 6.5 Creedmoor is flatter shooting than 7.62x51 out of a 16” barrel but at what price?
So in running the numbers today of various 308 projectiles of varying weight and BC vs 6.5CM in 130-140gr projo's in the 2300-2500 range and here's basically the gyst of what i'm seeing in terms of external ballistic performance:
Roughly 0.5 mil less hold at 1000y (with 10mph full value/90degree wind) in favor of 6.5CM (calculated 3.0 vs 3.5 mil hold)
Roughly similar ranges achieved when approaching trans-sonic velocities...no more than 70ish yards difference at approaching 1300fps
The point being this:
While 6.5 CM holds the external ballistic advantage...however slightly at these speeds, is it worth it for:
#2 ) barrel life
#3 ) ammo costs
#4 ) likely more costs on terminal effect due to the 6.5 being more of the fish-out-of-water at those speeds noted above in relation to expansion threshold and inherently lower energy numbers
If I weren't responsible for my gun (barrel), the ammo or the morality of terminal effect, 6.5CM it up and bring on the MRGG!!!
I gotta be honest fellas...I'm a fan of 6.5mm going back to before the existence of 6.5CM...
https://i.imgur.com/r2UFjLz.jpg
And even considering a lighter boltgun at 18ish inches, that even has me on the fence and leaning 308 given logistics.
Yea, I wish we knew the real numbers. We beat the shit out of our 6.5 guns, especially the AR10 where we load up a mag of 20 and send it. And we just suck at tracking round count.
Seems odd the numbers we hear about burning these barrels out vs 308 seem a little extreme. And as long as my guns will shoot MOA, I'm not changing a barrel.
PB
Thank you for the above comments. It confirms what I read/researched a few years ago when we started seeing AR-10s on the market in 6.5 Creedmoor. The round makes sense in 20-26” platforms. Yes, there is still an advantage using a 16” barrel, but you lose out on other things. It’s the whole package that counts. Of course, enter Sig .277 Fury as an example: a .308 case with a 6.8 mm bullet loaded to high pressures. It will be interesting to see how all of that works out. Nobody can give me data on barrel life for AR-10 platforms in this caliber; I’ve only seen bolt gun data, and barrels are lasting 3000-6000 rounds (stainless steel of course) from what I’ve read on the internet. Guys I know and work with who shoot PRS stuff are pushing 6 mm GT or Lapua variants now over 6.5 Creedmoor for various reasons in competition as well. It’s all good and crazy at the same time, but for most of us, .308 will do the job quite well and we get cheap M80 ball ammo for tactical courses, multigun, etc.
I like the 16” AR308 I put together; using the same WC barrel OP mentioned, WC rail and aero receivers it weighs less than a 8 lbs. FWIW with a 140 gr ELDM and 41.5 gr of H4150, averaging 2581.
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With today’s political climate I decided to start my journey by ordering a Stag10 blem lower in FDE, and a matching FDE upper. I’m still leaning toward a 16” barrel, but may go 18” depending on pricing and availability.