Welcome to AR10T.com, the world's first forum dedicated to AR-10™ rifles .  We invite you to JOIN our friendly firearms enthusiast forum.

× Participate in designing the AR10T.com Ultimate AR-10 Rifle! Based solely on the members of this site. The UAR-10 will be a true reflection of the design concepts wanted by this community.

.243 anywhere?

  • Posts: 268
  • Thank you received: 1

Replied by donkey1984 on topic Re:.243 anywhere?

So in other words your saying that .243's wears out Quicker? i just want to make sure that i am understanding you correctly. also where do you work/teach at msh?
14 years 5 months ago #2201

Please Log in or Create an account to join the conversation.

  • Posts: 90
  • Thank you received: 2

Replied by weshowe on topic Re:.243 anywhere?

Gents,

As I alluded to earlier the problem with the .243 is the ER(expansion ratio) of the cartridge based on case volume.

While the .223/5.56 will have a capacity of about 24.0 grains the .243 has a capacity of about 45.0 grains depending on powder used. Case capacity using water can be used as well, but the real problem is that you are trying to push a higher volume of hot gas down a very small bore. Which is why barrel life with a .223 is normally very good. Drive the same bullet down a bore with 45.0 grains of powder (.22/243 bore) and you will burnout the barrel in short order.
In short you are forcing double the volume of hot gas down
bore with the .243 vice that of a .223. Bad ju-ju for barrel life.

Wes
14 years 5 months ago #2202

Please Log in or Create an account to join the conversation.

  • a Guest
  • a Guest's Avatar
  • Visitor
  • Visitor

Replied by a Guest on topic Re:.243 anywhere?

Who ask I am retired now but teach part time at Motgomery Community College gunsmithing program. Also Sr. eng support for SOTIC part time. I make up barrels 3 days a week and do the special chamber jobs for Lilja rifle barrels. So who ever ask back up the line here it is.MSH
14 years 5 months ago #2209

Please Log in or Create an account to join the conversation.

  • Posts: 268
  • Thank you received: 1

Replied by donkey1984 on topic Re:.243 anywhere?

So a .243 barrel would probably only last about 3 or maybe 4 thousand rounds right? Thanks again for all of the info guys.
14 years 5 months ago #2211

Please Log in or Create an account to join the conversation.

  • a Guest
  • a Guest's Avatar
  • Visitor
  • Visitor

Replied by a Guest on topic Re:.243 anywhere?

It's gone at 2000 rounds.MSH
14 years 5 months ago #2212

Please Log in or Create an account to join the conversation.

  • Posts: 268
  • Thank you received: 1

Replied by donkey1984 on topic Re:.243 anywhere?

well scratch that idea. Is a 7mm-08 any better?
14 years 5 months ago #2213

Please Log in or Create an account to join the conversation.

  • Posts: 268
  • Thank you received: 1

Replied by donkey1984 on topic Re:.243 anywhere?

i figure a 7mm-08 is 1 more mm bigger in diameter so maybe it is a little easier on barrels and still has a little flatter trajectory. And i still have room in the safe for another one.
14 years 5 months ago #2224

Please Log in or Create an account to join the conversation.

  • a Guest
  • a Guest's Avatar
  • Visitor
  • Visitor

Replied by a Guest on topic Re:.243 anywhere?

The smart play on this one is to go 260 and extend the gas system 4 inches and its got good barrel life and is close to the 6.5-284. The key is to extend the gas or you'll be stuck at 2600 fps. 2800fps is much better the other way. The 708 is a poor choice on gas guns.MSH
14 years 5 months ago #2226

Please Log in or Create an account to join the conversation.

  • Posts: 268
  • Thank you received: 1

Replied by donkey1984 on topic Re:.243 anywhere?

alright thanks a ton for the info
14 years 5 months ago #2227

Please Log in or Create an account to join the conversation.

  • Posts: 73
  • Thank you received: 8

Replied by Scaup58 on topic Re:.243 anywhere?

>>> The 708 is a poor choice on gas guns.MSH

Interesting comment, care to elaborate? Not that I'm contemplating one, I'm the guy that want's to build a .22 Middlestead, but I am curious.
14 years 5 months ago #2251

Please Log in or Create an account to join the conversation.

Show 'em Off!

Add your rifle to the AR-10 Photo Thread!