308 - can large projectiles change the way a rifle shoots??

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308 - can large projectiles change the way a rifle shoots??

Post by TassieTiger » 10 Mar 2019, 5:29 pm

Went spotting with a mate today who wanted to do some load development.
He has a sako 85 (1/10 twist) shooting in 308 with a vortex 6-24 scope and he shoots 100m 1 inch groups all day with 150’s sst.

Today for giggles(he is doing a pig trip and wanted to experiment) he tried some 200gn eld s to see how they might go and as expected they shot low and about 2 inches lower.

What was really concerning - after 10 shots of the 200’ he went back to the 150’s and accuracy had fallen off quite dramatically really - his absolute best group measured 2.25 inches and many had an occasional flyer of which was not previously there.

Has he potentially damaged some rifling or throat by shooting the larger projectiles? Or should he be looking at something else?
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Re: 308 - can large projectiles change the way a rifle shoot

Post by No1Mk3 » 10 Mar 2019, 5:51 pm

G'day TassieTiger,
Very unlikely to have altered the throat after only a handful of shots, but possible to have fouled the bore. Has he undertaken a good cleaning regimen since changing loads? many years ago a friend and I shared a Sako FinnBear in 308, and commonly changed loads for different hunts without any issues, other than more frequent cleaning, Cheers.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by tom604 » 10 Mar 2019, 5:51 pm

bigger bullet, bigger kick, may of loosened something,may of given him a minor flinch,clean/check everything and maybe get someone else to have a shot as well..that's all i can think of but others may may thing of something else :thumbsup:
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Re: 308 - can large projectiles change the way a rifle shoot

Post by TassieTiger » 10 Mar 2019, 6:24 pm

Cheers for replies.
I actually thought about the bigger recoil doing something the rifle wasn’t used to...but mounts were checked, rifle was field cleaned with rod and foam brush only - ie not a deep clean.
This rifle is my friends baby - he has allowed me to shoot it once and made me take my wedding ring off lol. It might well be a flinch because the vortex eye relief is pretty close to hitting the shooter.
Tikka .260 (Z5 5x25/52)
Steyr Pro Varmint .223 - VX 3
CZ455 .22 & Norinco .22 (vtex 4-12, bush 3-9)
ATA 686 U/O 12g & Baikal S/S 12g.
Adler a110 reddot
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Re: 308 - can large projectiles change the way a rifle shoot

Post by deye243 » 10 Mar 2019, 7:21 pm

As I see it it will be because of different layers of jacket and powder fouling (or carbon layers) try a good clean and some fouling shots with the sst and shoot for group .....
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Re: 308 - can large projectiles change the way a rifle shoot

Post by marksman » 10 Mar 2019, 8:49 pm

deye243 wrote:As I see it it will be because of different layers of jacket and powder fouling (or carbon layers) try a good clean and some fouling shots with the sst and shoot for group .....


+1 :drinks:
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Re: 308 - can large projectiles change the way a rifle shoot

Post by in2anity » 10 Mar 2019, 8:53 pm

Did you let it cool down before the switch back?
At what point does lack of maintenance become patina?
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Re: 308 - can large projectiles change the way a rifle shoot

Post by duncan61 » 11 Mar 2019, 2:14 am

Some powders foul the bore I am running 35gn 2208 in my .243 and after 20 shots the bore is still clean when you look up it.I used 2205 in my .222 and after 4-5 shots a white greasy residue was left in the bore yet in the hornet it did not happen.Good scrub and see how it goes.I have to use sweets 7.62 fairly regular in my .222 S/S yet the .243 with a steel barrel goes for ages before needing a good clean
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Re: 308 - can large projectiles change the way a rifle shoot

Post by straightshooter » 11 Mar 2019, 6:37 am

TassieTiger wrote:Went spotting with a mate today who wanted to do some load development.
He has a sako 85 (1/10 twist) shooting in 308 with a vortex 6-24 scope and he shoots 100m 1 inch groups all day with 150’s sst.

Today for giggles(he is doing a pig trip and wanted to experiment) he tried some 200gn eld s to see how they might go and as expected they shot low and about 2 inches lower.

What was really concerning - after 10 shots of the 200’ he went back to the 150’s and accuracy had fallen off quite dramatically really - his absolute best group measured 2.25 inches and many had an occasional flyer of which was not previously there.

Has he potentially damaged some rifling or throat by shooting the larger projectiles? Or should he be looking at something else?


You beauty!
It's time to spin the rifle accuracy diagnostics chocolate wheel.
Now give it a real good spin and away it goes clickety, clickety, clickety.........
Click, click, it looks like it is about to stop on barrel fouling, click, now it looks like it is about to stop on bedding, click, oh no, it stopped on scope problem!
That can't be it, this scope has a lifetime replacement warranty and besides it looks great, lets give the chocolate wheel another spin.
Clickety, clickety, clickety.........

Sorry, I'm in a sarcastic mood today.
"Anything is possible if you don't know what you are talking about."
"There is no expedient to which a man will not resort to avoid the real labor of thinking." Sir Joshua Reynolds
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Re: 308 - can large projectiles change the way a rifle shoot

Post by Bills Shed » 11 Mar 2019, 7:13 am

straightshooter wrote:
TassieTiger wrote:Went spotting with a mate today who wanted to do some load development.
He has a sako 85 (1/10 twist) shooting in 308 with a vortex 6-24 scope and he shoots 100m 1 inch groups all day with 150’s sst.

Today for giggles(he is doing a pig trip and wanted to experiment) he tried some 200gn eld s to see how they might go and as expected they shot low and about 2 inches lower.

What was really concerning - after 10 shots of the 200’ he went back to the 150’s and accuracy had fallen off quite dramatically really - his absolute best group measured 2.25 inches and many had an occasional flyer of which was not previously there.

Has he potentially damaged some rifling or throat by shooting the larger projectiles? Or should he be looking at something else?


You beauty!
It's time to spin the rifle accuracy diagnostics chocolate wheel.
Now give it a real good spin and away it goes clickety, clickety, clickety.........
Click, click, it looks like it is about to stop on barrel fouling, click, now it looks like it is about to stop on bedding, click, oh no, it stopped on scope problem!
That can't be it, this scope has a lifetime replacement warranty and besides it looks great, lets give the chocolate wheel another spin.
Clickety, clickety, clickety.........

Sorry, I'm in a sarcastic mood today.


Maybe a bit tounge in cheek but , 10 opinions for a unanswerable question. None of them are wrong..but there can only be one winner, roll up, roll up. Enjoy the ride, Good luck.

Bill
Swaging your own projectiles is the ultimate in flexibility.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by TassieTiger » 11 Mar 2019, 9:09 am

The question we kicked around at the time, was technically based around metallurgy - and we don’t have a clue, just asking...
We spoke about rifling getting used to a pattern / size / weight of cartridge. Then it was along the lines - Does a heavier projectile touch a ever so slightly different part of the rifling and throat than a lighter projectile - and if so, could minuscule wear pockets then effect the previous “norm”....
Tikka .260 (Z5 5x25/52)
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CZ455 .22 & Norinco .22 (vtex 4-12, bush 3-9)
ATA 686 U/O 12g & Baikal S/S 12g.
Adler a110 reddot
Sauer 30-06 - VX 3
Howa 300 win mag. SHV 5-20/56
Marlin SBL 45/70
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Re: 308 - can large projectiles change the way a rifle shoot

Post by Sergeant Hartman » 11 Mar 2019, 9:50 am

The 1.10 twist is designed for heavier proj. 200 is as bit too heavy to get out fast enough to be worth it ballistic wise from a 308 but it will not destroy your barrel.

Why it shot worse I dunno.
Last edited by Sergeant Hartman on 11 Mar 2019, 10:10 am, edited 1 time in total.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by Bills Shed » 11 Mar 2019, 9:52 am

Definatly possible, give it all a go and let us know how you went. Me, I think the rifle /shooter was just having a bad day. Sometimes you go out and shoot like crap for no known....obvious...reason and then you come back the next and all is good. It may have been the rifle or the shooter. Sometimes it just works.
Good luck

Bill
Swaging your own projectiles is the ultimate in flexibility.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by SCJ429 » 11 Mar 2019, 10:37 am

I know guys who will not shoot two different powders over the top of each other and for the sake of a quick clean why would you.

I would suspect copper fouling may be the problem and since it is easily resolved with some copper solvent, it is a good place to start.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by Urbanbushman » 10 Apr 2019, 7:12 am

Back to basics! Check all the nuts and bolts, deep clean the barrel, go to the range (in a good frame of mind!!) check zero, (couple of fouling first of course) send plenty down range, have a great day! Now on level ground you can start load development or trialling different brands and weights, good luck and enjoy.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by Madang185 » 10 Apr 2019, 9:18 am

I would suggest a check of the twist rate that the projectile requires.
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Re: 308 - can large projectiles change the way a rifle shoot

Post by TassieTiger » 10 Apr 2019, 11:16 am

He cleaned the rifle thoroughly and it returned to shooing 1 inch groups with the 150's....seems the 200's must have left some fouling in the rifling to some degree...
Tikka .260 (Z5 5x25/52)
Steyr Pro Varmint .223 - VX 3
CZ455 .22 & Norinco .22 (vtex 4-12, bush 3-9)
ATA 686 U/O 12g & Baikal S/S 12g.
Adler a110 reddot
Sauer 30-06 - VX 3
Howa 300 win mag. SHV 5-20/56
Marlin SBL 45/70
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Re: 308 - can large projectiles change the way a rifle shoot

Post by marksman » 10 Apr 2019, 12:10 pm

funny thing that :wtf:

thanks for letting us know :thumbsup:
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