6.5 Creedmore instead of .308?

[Bart B.]

Lengthen the 308's throat 1/10 inch or more and you can shoot up to 250-gr. HPMK's with decent powder charges.

 

[MCMXI]

Lengthen the 308's throat 1/10 inch or more and you can shoot up to 250-gr. HPMK's with decent powder charges.

And still have the rounds fit in standard length magazines? AI pattern magazines for example?

 

[COLOSHOOTR]

And still have the rounds fit in standard length magazines? AI pattern magazines for example?

I don't think that would work either. I'm still not seeing the benefits to a heavy. 308 loaded that hot and that long. For target shooting it does nothing over the 6.5mm offerings. Also, if we are talking ELR Military/LE or hunting applications I still wouldn't use the heavy .308 as going with a 300 win mag or .338 lapua would likely be better options. Especially when we are talking magazine fed systems...

 

[Ks5shooter]

If you are just punching paper informally, the 243 winchester will do anything those two will with far less recoil and you can find ammo anywhere.

I agree and I reload,but Im not gonna shoot more than 400 yards, so I bought the .243 .Its cool need to put glass on it now.

 

[DocUSMCRetired]

I am just going to follow up on some stuff here.

1. Here is a magazine coal length chart, so you can see what will and wont fit in different magazines: http://www.abmediaresources.com/AppliedBallisticsMagazineLengths.pdf

2. Here is why the .264 over the .308: http://www.abmediaresources.com/articles/ABDOC110_WhatWrong30Cal.pdf

 

[Bart B.]

I'm still not seeing the benefits to a heavy. 308 loaded that hot and that long. For target shooting it does nothing over the 6.5mm offerings.

Compare the Sierra .308 240-gr. HPMK leaving 2200 fps from a .308 Win. to the Sierra .264 142-gr5-gr. HPMK leaving at 2600 fps from the 6.5 Creedmore for wind drift at 1000 yards. Those are max, safe loads will do for each cartridge.

The .308 has twice the barrel life of a .243 Win and 50% more than the .260 Rem or 6.5 Creedmore. This applies if barrel life is a compromise.

 

[Offfhand]

Quoted from above post:
"The .308 has twice the barrel life of a .243 Win and 50% more than the .260 Rem or 6.5 Creedmore."

50% more barrel life than .260? This is so totally wrong it's almost funny. Make one wonder how these rumors get started.

 

[Bart B.]

Challenge Sierra Bullets for those barrel lives numbers. That's what they get in their test barrels before accuracy with their control lots of bullets (called "standards") when accuracy degrades 50% from when new starting out at 1/4 MOA average at 200 yards. Competitive match rifle shooters wearing out their barrels for each producing the best results also get those numbers from those cartridges. David Tubb was not surprised when his .243 Win. barrels got 1500 rounds of barrel life as predicted by Boots Obermeyer.

If someone wants to use a different standard, so be it. They may well get 7654 rounds of barrel life with theirs.

 

[MtnCreek]

I have no idea about the 308 / 240 load, but the 6.5 / 142 load is on the slow side.

 

[COLOSHOOTR]

Challenge Sierra Bullets for those barrel lives numbers. That's what they get in their test barrels before accuracy with their control lots of bullets (called "standards") when accuracy degrades 50% from when new starting out at 1/4 MOA average at 200 yards. Competitive match rifle shooters wearing out their barrels for each producing the best results also get those numbers from those cartridges. David Tubb was not surprised when his .243 Win. barrels got 1500 rounds of barrel life as predicted by Boots Obermeyer.

If someone wants to use a different standard, so be it. They may well get 7654 rounds of barrel life with theirs.

The problem is we are not talking. 243 (6mm), a known barrel burner, but instead are talking about thr .264 (6.5mm) so barrel life comparisons between. 243 and .308 are off the topic. The .264 will get less barrel life than the .308 but we are only talking 300fps more velocity between the .308 and .264 cartridges (.260, 6.5 CM or 6.5x47 Lapua) and a couple of those 6.5 cartridges have a more efficient case design. The barrel life chart you posted seems short compared to what I've seen in real life and not what I read online. Mr. Tubbs tossing his .243 after 1500 does not surprise me one bit but he is not "the average shooter" and runs loads in excess of 3000fps for that competitive edge. That's going to toast any barrel.

Please post a link to the Sierra testing so wee can actually see the fine print for their testing criteria. Without the fine print it's hard to decide how valid that test would be for the majority of people. If the test involved running the different cartridges at maximum pressure and velocity it's not really going to be valid proof of what will be seen here in the real world where few are running their loads that hot.

 

[Bart B.]

Sierra's tests were at normal, SAAMI average max pressure same as commercial ammo. So were all the others I gleaned data from.

Contact Sierra direct then get answers from them if you don't believe what I said. That way, you get them first hand like I did from the people testing their bullets for accuracy shooting many 10-shot test groups per production run.

Of course, if one gets less than 1/4 MOA average at short range and it's in the 1/2 to 3/4 MOA range, they'll get twice the barrel life. Military accuracy in the 1 to 2 MOA range gets them three to four times the barrel life.