Nosler 223 80gr projectiles breaking up

[macguru]

Recently, I have had problems with Nosler 223 80gr projectiles breaking up in mid flight and was wondering if anyone else has had it happen to them . At first, it was the odd one would not make it and we were not sure what was happening , but recently I had only 24/40 shots make it to the target in a session, and shooters on either side of me could see the puff when they let go ! (the 24 that made it were all in the 9 or 10 ring despite a windy day)

Reasons, as I see them.
Fast twist barrel 1:7 savage
thin jacketed projectiles
maybe the rifling is cutting them a bit deep ?
more failures as the barrel heats up...

this, despite moderate velocity about 2900fps in a 26" barrel. I might add that ALL of the sierra 223 80 grainers i have used have made it downrange no problems, and I am now using them exclusively.

[Peter Marum]

1:7 krieger
2940-50 fps
puffs of grey 100 mts down range
shouse accuarcy
a real pita, ordered a new 1:8 Maddco, bin the kreiger

[RAVEN]

Who chambered it?

[macguru]

I am getting fantastic accuracy from my 1:7 savage
some of the sierra loads are under 1/2 moa, the noslers were better but obviously not reliable, however amax were less happy with group sizes twice as big as the other two.

were your failures with noslers ?

[M12LRPV]

1681 of them through a Savage 1 in 9 without a problem.

670 of them through a Krieger 1 in 8 without a problem.

Perhaps it's just an issue with the 1 in 7?

A friend has just bought a savage 1 in 7 and is using Noslers so i'll see how he goes.

[Gadget]

Hi
I punch them out at 3200 fps in a 1:8t 28" Hart, but in a 22BR and have never had one let go.

I read this on 6BR the other day and found the RPM interesting not your specs but the formula is at the bottom of post
Quote
At 3000fps in a 8 twist your bullet is rotating at 270,000 rpm, at 3000fps in a 9 twist the rpm is down at 240,000. you are most likely over spinning the bullet at that velocity
To slow the rpm down to equal a 9 twist you need to slowdown to 2700rps in the 8 twist. I suggest you try reducing you load gradually until the bullets hold together - also call Sierra tech line and ask the rpm capability of the 180 vxs the 175,
End
formula : mv fps X 12 / twist in inches X 60= RPM

So if the formular is corect, your numbers show about 37,000 rpm faster than a 1:8 twist
2900 x 12 = 34800 / 7 twist x 60 = 298285 rpm
2900 x 12 = 34800 / 8 twist x 60 = 261000 rpm
BR @ 3200 fps = 288000 rpm
Gadget

[macguru]

Yes, the above formula is correct. Hopefully the problem will not be common to other brands of projectile, because the best speed for me seems to be between 2800 and 2900 fps.

Also, I emailed Nosler and they messaged me back asking for the lot number etc, so i will post their reply here when i get more from them.

LRPV, Does the 1:9 barrel handle 80gr projectiles ok ? I assume we are talking about the same ones ie 80gr .224 nosler match, 80gr sierra matchkings and 80 gr Amaxes....... Have you noticed any odd ballistics ?

Also, I am going to try the 90gr sierras sometime, just as an experiment. (just for informal shoots or F open not Std)

[M12LRPV]

LRPV, Does the 1:9 barrel handle 80gr projectiles ok ?

It's a true 1 in 9" (measured) and handles 80gr Sierras and 80gr Noslers but not the 80gr Amax's.


On the issue of breakups...
Are the loads compressed? Is the seater damaging the jackets trying to compress the charge in the case?

[macguru]

The loads for all 3 projectiles are slightly compressed (2208) but there is no sign of any stress on the jackets from the loading process so i dont think that would be a factor..........

[littlebang556]

too have had Noslers AND Amax dissapear as if like magic under various different loads and powders and from 2 barrels (Both 7.7T).
I am yet to have a single shot do this with the only other allowed 5.56 proj (Sierra) in Aust TR... To me, it is nearly like comparing apples to oranges...
When I can weigh a box of Sierras (500) and have an ES of 0.2gn max and 2 thou difference in base to ogive I see no reason to apply my hard earnt dollars on inferior (n my opinion) counterparts. If my final shot in a competition is a 4 then I can handle that but if it went AWOL for one reason or another then that is difficult to take...

[macguru]

Well I have fired about 200 sierra 80s so far and NONE of them have gone missing so i guess they have thicker jackets allright........ I have not heard back from Nosler since i emailed them the batch number for their 80 grainers.......

Also I am going to try some 90grain Berger VLD and maybe sierra 90s in Fopen and I was wondering whether any other !:7 twist 223 shooters had any load advice or comments regarding the 90grainers ? I was thinking around 23gr of 2208 COAL about 2.5" (not sure about the coal til i get the ones i ordered (VLDs))

cheers andrew

[littlebang556]

There are a few people mucking around with the 90's and for the time they have taken in getting results I personally would not bother with a barrel that has the required fast twist...Instead, i would be looking at a 7 to 7.5 T barrel and running something a touch heavier than 80gn...maybe 82...This weight is not allowed in competition in AUST TR so not worth me trying it but would love some1 else or even an F Class shooter to give it a blast.