Any interest in the 6.5 Grendel?

tahunua001 said:

well I bet he doesn't taste nearly as good.

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well we cant really be certain of that.. unfortunately my dog is too old to eat and find out

Hey Justin. Since you want us all to think you know what you are posting about. Explain to a dummy like me what you call bolt thrust, is. What directions is the thrust you speak of being applied to said bolt. That way a neophyte such as myself can figure out if said Bolt Thrust could be breaking the lugs on ar rifles. Please no one else chime in, I want the real deal from Justin.

Chillax bro, there'll be no measuring of anything; this is a family joint

Also, if you don't think chamber pressure delivers thousands of force (impact force, no less) to the locking surfaces of a rifle action, I dunno what to tell you. For some reason there's this thing where some folks believe a thin brass tube is capable of withstanding several times its yield stress, and carries nearly all the chamber pressure loads via friction against the chamber walls.

Some folks just refuse to accept science and/or math; like the tool over on PracticalMachinist who insists harder steel is mechanically stiffer than softer steel in bending. It's been measured countless times on stress/strain tables, yet he refuses to contradict his 'gut instinct' on the matter

TCB

Casefull said:

Hey Justin. Since you want us all to think you know what you are posting about. Explain to a dummy like me what you call bolt thrust, is. What directions is the thrust you speak of being applied to said bolt. That way a neophyte such as myself can figure out if said Bolt Thrust could be breaking the lugs on ar rifles. Please no one else chime in, I want the real deal from Justin.

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bolt thrust is figured out by the surface area of the inside base of the cartridge multiplied by chamber pressures.. the pressure that pushes the bullet forward is also pushing the cartridge, as well as the bolt backwards, your locking lugs is what prevents the bolt from flying back through your eye socket under those same forces propelling your bullet forward

a .223/5.56 exerts over 4,000 pounds of thrust backwards into your bolt.. so everytime your pull your trigger the amount of thrust exerting against your bolt goes from 0-4,000 in a mere milliseconds

there are two ways to increase bolt thrust, first way is by increasing the surface area in the bottom of the case (by using a larger diameter cartridge case) and the second is by increasing chamber pressures.. therefor when your bolt can only handle a specific amount of thrust and the diameter of the cartridge case goes up, chamber pressures MUST go down or you risk breaking lugs

To be clear, the issue in the first place is that there isn't much left over strength margin in the AR15 bolt. Practically every other design has a proper 2X-3X (or more) margin, but the AR was so efficiently (read: lightly) designed for the specific 223 cartridge, t'aint no way to bump up the power much at all. No room to get wider in the case due to bolt strength, and even less room to get longer in the case due to the magwell.

For the 'most modular blah-blah-blah' ever devised, it really does have some fundamental limitations as far as chamberings go (luckily and/or coincidentally, there's a veritable cornucopia of cartridges at or below the AR's limit). I've always said that someone needs to blow out the front of the magwell & incorporate it into the upper, so longer cartridges capable of delivering more power at reasonable thrust levels may reach their potential from longer and/or larger bore barrels.

Even better would be a stronger bolt/extension design, but this would mean giving up the AR's exceptionally small unlocking cam angle (small due to very narrow, but more fragile lugs)

TCB

its only the most modular and most versatile due to an almost non stop decades long pandering to it.. most of the time when someone makes the claim the AR can be adapted to fire so many different cartridges its only because so many have been made to pander to its limitations, from 22lr conversions all the way up to the extremely low-pressured 50 beowulf.. had the beowulf not been down-pressured to chamber pressures lower than a 9x19mm cartridge and was even remotely close to the pressure 5.56 operates at, youd probably kill yourself the first time you pulled the trigger

The Beowulf runs just barely under 357Mag pressures, and does
just fine for what it was intended: Big/Heavy bullets able to smash
through most anything from a mid-sized frame -- and do it round
after round after round after round ...after highly controllable round.

6 rounds in 9 seconds at swinging 8" steel gong /100yds

But justin22885 has a software app that says it won't.

...and I'm done with this thread. it had such a great prospect, but one guy who has nothing but negativity to add and a couple guys who think they have the magical power to change a close-minded opinion have made it a giant loopdeloop of yeahhuh-uhuh-yeahhuh-uhuh... well, they've basically removed any entertainment or educational value this thread had.