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6mm-284 or 6.5-284


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So decided on rebarreling a T3 doner action I have in 6.5-284 and shooting 130-140 VLD's out to a 1000 but started running data on 6mm-284 with 105's, they're impressive!! Apart from there being a bit more brass prep and a even more reduced barrel life with the 6mm is there any other pro's and con's of the two?

 

Have heard it mentioned that the 6mm can be a bit fussy to get a good load developed for it??......

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Had a few 6-284s. Brilliant 1000 yard BR round but barrel-life is short - very short! Not too fussy on load-development.

 

Despite its performance in competition, I'll not build another.

How short Vince?

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Well, in 1000 yard benchrest competition, you are firing 5 rounds in around 15 seconds. That's hard on barrels - 400 to 450 rounds if you want to maintain half MOA accuracy out to 1000 yards.

That is short! But if you for instance were using it for fox with maybe one or two shots a night would barrel life significantly increase?

Would it achieve 1500 rounds or is that too optimistic?

 

Sorry ABR for hijacking your post.

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Andy,yes-foxing barrel would last longer.

Many variables,but calibre,presure and heat (powder and amount) AND rate of fire are the main ones.

 

cf "typical' acceptable life:

308 5000

260 2500

243 1800

All very approx,but indicates in essentialy the same case,the effects of 'overboring'-hot in smaller bore.

 

Would you get 1500 fro 6/284-just maybe,it's gor more powder than 243.....but cold barrel each time....?

 

Accuracy Tech has a good readable article -"Barrel life"

Accurate Shooter has too,with the Excell spreadsheet calculator "Barrel Life Spreadsheeet"

 

As Vince says,a lot depends on useage rate-a machine gun used heavily will wear barrels a lot more than a single shot a year hunter!

 

But note too,what does 'toast/shot out' mean: for a competition shoooter deterioration from 1/4 to 1/2 moa might be unacceptable,but a hunter shooting at 150 yards might not even notice,and might well be ok with one moa,even more-many new rifles are not that good! This is quite a big consideration-potentially increasing barrel life a lot (depending on how fussy you are about first shot hit probability/group size-and probably accounts for the considerable differences casually reported by users of the 'same' cartridge).

 

 

Barrel life times in actual ' bullet in the barrel" are short- maybe 10 seconds for 5000 308w,more like 3 seconds for 1500 243) !!

 

gbal

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Sorry ABR for hijacking your post.

It's cool man, all good info for me also!!

 

I'd say that your barrel life would double, maybe even 1000+ only firing single shots at foxes. It's the temperature that erodes the throat firing rapid or long strings.

 

For vermin and targets out to 1000y it really does look like it trumps the 6.5, just a shame about barrel life.

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I have a 6-284 it has a 1:14 twist, and i have had it since 2004. I use a 68g match bullet in it and only use it for foxing. The most shots i ever fire at a paper target would be 10. The first barrel had a round count of 950, can't remember how long that was in time. I didn't find the accuracy fell off, but i started getting pressure signs, which was due to what the gunsmith described as severe fire cracking. I think the rebarrel cost £450 i think which i didnt think was to bad for the enjoyment i got out of it.

The round count on this barrel is now just under 800, and on a good day (for me that is) is sub 1/2 min all day.

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I have a 6-284 it has a 1:14 twist, and i have had it since 2004. I use a 68g match bullet in it and only use it for foxing. The most shots i ever fire at a paper target would be 10. The first barrel had a round count of 950, can't remember how long that was in time. I didn't find the accuracy fell off, but i started getting pressure signs, which was due to what the gunsmith described as severe fire cracking. I think the rebarrel cost £450 i think which i didnt think was to bad for the enjoyment i got out of it.

The round count on this barrel is now just under 800, and on a good day (for me that is) is sub 1/2 min all day.

 

 

What sort of speed you getting with that bad boy?

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What sort of speed you getting with that bad boy?

I had an identically built rifle to 17 Squirrel's, 26" 1:14 and was getting 4000 fps with 68g Barts, but could push this to 4150fps with less accuracy this was with N160. It was rebarrelled after approx 750 rounds with no drop off in accuracy, I just fancied a change, it was rebarrelled with 27" 1:10 and was shooting 87g Bergers and 87g Vmaxes at almost 3600 fps with N560 and no pressure signs, it has just had chop to 24" and not had a chance yet to check loads.

Only used for fox and very slow shot string load development, HTH

I remember Vince telling us about his previously and from memory it was a slightly shortened version, did I recall that correctly Vince?

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I had an identically built rifle to 17 Squirrel's, 26" 1:14 and was getting 4000 fps with 68g Barts, but could push this to 4150fps with less accuracy this was with N160. It was rebarrelled after approx 750 rounds with no drop off in accuracy, I just fancied a change, it was rebarrelled with 27" 1:10 and was shooting 87g Bergers and 87g Vmaxes at almost 3600 fps with N560 and no pressure signs, it has just had chop to 24" and not had a chance yet to check loads.

Only used for fox and very slow shot string load development, HTH

I remember Vince telling us about his previously and from memory it was a slightly shortened version, did I recall that correctly Vince?

 

Yeh - I did a shortened version in the hope of getting a better case-fill. I did - but it wasn't worth the extra trouble of case-forming.

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Had a few 6-284s. Brilliant 1000 yard BR round but barrel-life is short - very short! Not too fussy on load-development.

Hey Gun Pimp,

 

Were you shooting 105's and 115's in yours, if so what kinda velocities are achievable?

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Hey Gun Pimp,

 

Were you shooting 105's and 115's in yours, if so what kinda velocities are achievable?

 

I tried the 115 DTAC and Berger but it always worked best with 107gn Sierras. These have a thicker jacket than most 105s. You can drive 'em at 3400+ but then I used to get messages back from the butts "Nice group but only four shots!"

 

Run 'em too fast and they'll blow! I used to stick around 3250fps.

 

You can get almost equal performance with a 243 Ack. but the barrel doesn't last any longer and it doesn't quite have the consistency of the 6-284.

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I tried the 115 DTAC and Berger but it always worked best with 107gn Sierras. These have a thicker jacket than most 105s. You can drive 'em at 3400+ but then I used to get messages back from the butts "Nice group but only four shots!"

 

Run 'em too fast and they'll blow! I used to stick around 3250fps.

 

You can get almost equal performance with a 243 Ack. but the barrel doesn't last any longer and it doesn't quite have the consistency of the 6-284.

Thanks for your help, much appreciated!! ;-)

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  • 1 month later...
  • 1 month later...

Just my thoughts , I have a 6 x 284 , 6.5 x 284 , 6.5 wsm & 7/270 wsm's and nothing beats the 7mm's . Vince is right regarding the heat created by either fast firing of five shots or quickish firing of 2 & 15's or 2 & 20's in comps but half a dozen rounds over an afternoon is worlds apart in barrel wear .

My finding on the 6 x 284 were in calm conditions it shot like a dream but on reflection most good rounds would like BR's , Dasher's , 47's etc , But the moment the wind picked up you wished you'd brought a 7 .

If i wanted one rifle to fit all out of the above and i wasn't going out too far then i'd run the 6.5 x 284 over the 6 x 284 but running a 7mm slowly would still beat them both with ease .

 

OSOK

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Just my thoughts , I have a 6 x 284 , 6.5 x 284 , 6.5 wsm & 7/270 wsm's and nothing beats the 7mm's . Vince is right regarding the heat created by either fast firing of five shots or quickish firing of 2 & 15's or 2 & 20's in comps but half a dozen rounds over an afternoon is worlds apart in barrel wear .

My finding on the 6 x 284 were in calm conditions it shot like a dream but on reflection most good rounds would like BR's , Dasher's , 47's etc , But the moment the wind picked up you wished you'd brought a 7 .

If i wanted one rifle to fit all out of the above and i wasn't going out too far then i'd run the 6.5 x 284 over the 6 x 284 but running a 7mm slowly would still beat them both with ease .

 

OSOK

 

"The good Lord giveth......."

 

I'm reminded of a variant on Einstein's uber question: "when god the made the laws of ballistics ,and the 7mm proved superior,was there any real choice?"

 

gbal

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Yes I'm guessing that's a decent size variant ...... Not sure what he would have made of someone like me as i think he said ' A clever man solves a problem , A wise man avoids it to start with ' I sometimes seem to create a problem so i can solve it were shooting is concerned :wacko:

 

OSOK

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