My shooting buddy had a 223 built to shoot heavy bullets (70 to 80 grain) but can not get the accuracy expected. The rifle loves 50 grain bullets and holds them to less than 1/2 inch. With 55 grain on up the groups open up as the bullet weight increases. The 1 in 8 twist likes the lighter weight bullets. 70 to 80 grain bullets open groups to 1 1/4 to 1 1/2 inches! Any thoughts?

<img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

Jim

Need to check if it really is a 1:8 twist barrel.

How many rounds down the tube? Is it broken in yet?

I agree. My 1:9 twist barrel doesn't start getting really tight groups until I start using 68, 69, or 70 gr. bullets.

As described it sounds more like a 1:12 twist barrel....

It's broken in with around 90 - 100 rounds.

He says he verified the twist.

Damnit..........

How's it throated? Are the heavies pole-vaulting to the lands?

Is it an AR?

Kiss lands and carry on....................

Could still be a lot of things.

Box ammo or handloads? If handloads, which powder and primer?

How long of barrel?

Barrel length would have zero bearing,unless velocity was so compromised,that boolits weren't stabilized..................

That is why I asked the question.

Unfortunately...or fortunately....98% of any problem...is solved by the basics.

So..if you ask the basic questions...the problem will be found sooner.

This rifle is a re-barreled Sako ( L-46? ) with a medium sporter weight barrel. Powder is Varget and Benchmark with Sierra and Hornady bullets in weights of 50, 55, 60, and 69 gr. I do not know charge weights or primer data.

It is not my rifle so I don't know all the details of his loads. Sorry.

Jim

Barrel length 100% of the time,means dick on 100yd paper...................

The Baby Sako's have an itty-bitty mag box and my guess is that the 8" twisted tube's throat is cut for heavies and he's pole-vaulting them to the lands.

I'd go to kissing lands,disregarding mag confine COAL,as a barometer of performance evaluation.

The 64gr PP will probably shoot very well via mag confines(ogive friendly to the Sako),but the BC is [bleep].

Hammers Deer though.............................

I've got a box of the factory Win PP 64grainers sitting on my bench... explicitly for deer ... havent tried them at all yet ... still, I figure they'll do alright out of my 24" 1:9 twist pacnor 3 groover .... <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

They'll do nicely outta a 12" twist.

Have killed alotta Deer with them.

They dig deep....................

my .223 is twisted 1:9", so I've no hessitation in using them ... Just haven't gotten 'round to it yet ...

Well..you are not subtle.

no ... he's not, unless you get one of his posts in "stick language" that might be hard to interpret ... but even then, it's not subtle ... just a little harder to figure out, if you're not used to his style of writing ...

EDIT TO ADD: Regardless of the above, he's full of good info, as he shoots everyday, and has (or has had) a rifle in just about every reasonable chambering and style ... I can't speak for anyone other than myself, when I say that I've learned a lot from him ... a whole lot ...

What in the world is his pen name-- i gotta check out some of his stuff.

My AR in a 1-9 does not like heavy bullets either. I think the 223 is at its best in the 40-50 grain. And the Swift and 22-250 is best with 50-55. Not based on barrel twist, just based on case size and charge. The 223 in not a burner anyway, so I cannot see slowing it down with heavier bullets. That is just my preference though, I just never understood why people want to shoot heavy bullets from a small gun.

Well said! If I want a heavy bullet I use a larger cal. My .223's like 50 gr. and I don't use anything else.

To each his own.

Jim

Takes a goodly sized motor,to whoop the 223AI/75-A-Max's ass at 3100fps,via 21" tube.

BT/DT and I've largely got 'em all,to compare/contrast............................

Who wants a varmint rifle only pushing 3k?

Whattya gonna shoot,to whip it's ass?

How many 75A-Max you seen impact Vermin,at what velocity and to what distance?

Nice not having to speculate.........................(grin)

JMHO, but I put no faith in 100 yard groups, let the long range targets tell you what bullets are working. Some of my 200,300 yard groups are just about equal, 400s and 500s really speak. Dial out the paralax, consider the 63gr Sierra, no equal in trajectory but accuracy seems dependable, in short boxed guns. Let us know, Bill

My Ar15, 1-9, loves the 69 Sierra Match Kings, I use 4895 powder, and with open sights, and my 61 year old eyes, I can hold an inch at 100 yds, and get 20 scoring in the black hits at 500yds during our DCM shoots. Pretty good performance!

As to these 75 grain 224 bullets flying down range, all one needs to do is pick ANY larger cartridge case, fill it with more powder, have an equal barrel length, with the proper twist, and Viola! the 223 AI's ass has been wipped, LOL!!!

Jerry

29MOA to 1000yds,from a 100yd zero,via 26grs of powder in a 21" tube,is pretty skookum in my book.

Weigh logistics,component costs,barrel life and total absence of recoil and it's tough to whoop up on.

My 22CHeetah don't impress me in nearly the same manner.......................

I took a big woodchuck facing away, just over the hips at an honest 500+ a little lasered yards tonight with the 223 WSSM and a 75 gr. A-Max. Should of been clocking right around 2300 at that range. Love seeing them drop and then hearing the whomp a few seconds later. To my surprise the bullet did not exit. I found the entrance hole and slit it open in hopes of maybe finding some bullet pieces. Atlas the inerds looked like they had been put in a blender and then reinstalled. Wasn't gonna finger through that stink'in mess.

Will try the 80A-Max on venison this year,as a curiousity.

Reports are,that they sport a heavier jacket,than the 75's.

Will know soonly......................

that bone is real heavy between the eyes <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

woofer

Always preferred a shot alongside the noggin',as opposed to head on,though I've done lotsa both...................

How about the 224 Clark?
Thats a smoker with 80 grn bullet at 3500 fps.
It reaches out and tuches em.
BGRS

At that level of case capacity,6mm's start makin' a buncha sense to me.

I love my 223AI's,far more than any of my 243AI's or the 6AI..........................

The .224 Clark is impressive but look at cases, barrel life and to many variables to get an extra 400fps.

The .223AI with the 75 Amax is extremely impressive. The jump in terminal performance from a 50gr vax to the 75 has to be seen to be believed, especially once stuff gets above the 30-40 pound size. For squirrels I love the 40 Vax at about 3800fps but past that the 75 gets the nod.

I've a CHeetah that sets on the sidelines,riding the bench,while a 223AI gets the ball on nearly every play...................

As you obviously know, 70 grainers (69 grains) would seem to work well in a 1 in 8 twist. Might be how the round is seated or the load. I would try some 69 grainers from Black Hills or some other 'factory load'. Just to test out the theory here. But right now as you have found out---it makes no sense that these 70 grainers would be big grouping at 100 yards.

However, my personal feeling is 55-62 grains is the ideal 223 weight and if you want a heavier bullet..............................

Go to the 243! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> ;

Mine shoots 80 grain bullets like a laser beam.

(My 223 shoots like a laser as well as long as I shoot 62 grains or less)

"Laser" is relative.

I quantify it by sight correction requirements,at a given distance.

The .435BC .224" 75A-Max via 223AI @ 3100fps,can smoke more than a few 243Win loads to 1K.........................

don't forget to add that the .223rem and .223AI has other merits ... like less powder to burn, longer barrel life, less report, less recoil, etc ... <img src="/ubbthreads/images/graemlins/shocked.gif" alt="" />

since I've owned a .223, I can't believe it took me so long to get to owning one ... it's by far the most fun rifle I have, and the one I shoot the most ... I can only imagine that the "improved" version is that much mo' betta' ... <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

I've been shooting the 80 AMAX for my LR loads this year. V140 and 540 in my AR match rifle. Can't for sure say they are better than 80 SMK, but they seem to require a bit less comeup at 600 and they shoot great.

I would think that were they would beat the SMK is if vermin were on the other end. Can't say the extra .02 BC is going to compensate for the extra 100 fps or so lost compared to the 75 gr. V-Max.
Regardless I have a box on tap once my current run of 75's is used up.

Am very curious to see how the 80'max slap [bleep].....................

What's your source on jacket thickness. Shot them in a Palma this weekend 8,9, and 1K. They hammered in my 223/vv540 @2950 ...145x8 at 1000 and the shots out were my call (me)

Cross-sectioning diagrams...................

Where do you get sectioned diagrams? I'm driving a Mitutoyo with a new battery and a 200 gram poly foam rubber....no difference in the jacket, but the heel on the 80 amax is thicker........which is very much of interest because of my 80 JLK experience (on paper).