.223 reload/barrel twist

[brewdog]

I am new to reloading. i just started with .223 used brass and was only able to find magnum primers and some 784 ball powder. Earlier today I was on some site that was talking about bullet wt and barrel twist. i have a 1:7 DPMS barrel on an Olympic Arms upper and was loading 55grHP into the cases with 27gr of powder. Does anyone see any danger in this or is there a site with more info on barrel twist and bullet wt?

[firewrench044]

The lightest bullet that my Bushmaster (7.5/1 twist ) will shoot acuratly
is 62 gr, the the faster twist barrels were made to shoot heavyer bullets

reduce max loads when useing magnum primers !!
my Sierra Manual lists 26.5 gr as max for 748 with 55 gr !!

I recomend a heavyer bullet, and when working up a load start with some test loads, working up from the min. not the max. watching for signs of too much pressure (read your book) as you fire test rounds one at a time and
inspect cases as you fire these test rounds

*** I recomend you disassemble those rounds and try again ( this will give you a chance to use the bullet puller that you should have ) ***

[amamnn]

The idea of matching bullet weight (which is REALLY matching bullet length) to barrel twist is to only allow the bullet to spin as many times in its trip from muzzle to target, as is necessary in order stabilize the bullet in flight. This aids accuracy, obviously.

The idea is that no bullet is perfect and one point on the circumference of the bullet is going to be heavier than all other points. Therefore, the fewer times the bullet spins, the fewer opportunities imperfections will have to affect the bullet's path. Heavier (longer) bullets must spin faster in order to stabilize in flight than lighter (shorter) ones.

So, since most people buy a rifle and then hear about this twist rate business afterward, the idea then is to select the bullet that will stabilize with the fewest turns. Depending upon the range and application for which the rifle will be used this may vary within certain parameters.

Selecting a bullet that is too heavy for the twist rate will result in a bullet that does not fly straight or may even tumble in flight. The results of this can be seen as very inaccurate groups, even to the point of bullets hitting the target sideways (keyholing) while selecting a bullet that is too light for the twist can result in inaccuracy, but it will not necessarily be so. One of the best groups I ever shot at a 200 yard BR target was done with a bullet that was and is considered much too light for the twist of the barrel I was using. Remember, we're trying to minimize bullet imperfections, and the 5 Berger 52 grain bullets I shot at the score target that day obviously were pretty close to perfect. If you load bullets that are wildly light for that 1/7 twist you may not only find them to be unpredictably inaccurate, but may have some come apart in flight. I have never had this happen, but I have talked to people I consider to be honest, who claimed it happened, so I have to believe it can.

I cannot see any danger in loading a 55 gr. bullet to be fired in a 1/7, but it is not the bullet I would choose. As far as sites with twist/bullet info - one of the best places you can go is the Berger bullets website, where they list their bullets by weight and also give you the SLOWEST recommended twist. that should give you all the info you need to make a selection.

http://www.bergerbullets.com/

[NuJudge]

The Sierra's have pretty heavy jackets, so they may take the velocity better than a thinner jacket.

Many years ago I shot some Varmit 50gr SX bullets in a 1:12" barrel, and the bullet jackets were beginning to peel out to the side. They left a grey smoke-like trail of Lead in the air. It really was kind of neat. Smoke tracers.

I believe you are trying to say that you are using Winchester 748 powder. I really like it with bullet weights in that class.

CDD

[m.p.driver]

More important is how are your groups?I wouldnt disassemble all your rounds
unless they're off the loading tables to be unsafe,or you're flinging them all over the countryside.

[lmccrock]

Does anyone see any danger in this

Just regarding twist rate and bullet choice, there is no danger. I have seen 55 gr bullets fly apart when fired from a 20" 1:7 barrel (not my gun, but I saw the results). No "danger", just unsatisfactory results. There are claims that a thicker jacketed FMJ will not come apart (like, military M193), but the groups open up. 1:7 is designed for heavy bullets, or longer ones like M855 or M856.

I have personally shot 68-69gr bullets from a 20" 1:12 barrel, and there was no such thing as a group. Some bullets went sideways. The same barrel shot 52gr match ammo like a laser beam. (I wanted a 1:8 or 1:9 but the builder grabbed the wrong barrel - he later replaced it with a 1:8).

Lee

[kraigwy]

No Sir, there is no danger (taking into account I didnt check your powder load).

I have a 1-7 White Oak Service Rifle for High Power. I use 77s & 80 SMKs.

BUT for 100 yard reduced practice, I buy the cheaper 55 gns. They shot good at 100 yards but not so well at extended ranges. Plenty good enough for 100 Yd reduce HP practice.

Its the other way around with using heavier bullets in a slower twist barrel. I'd be lucky to get the 77s or 80s in the black with my 223 Rem Bolt gun w/1-12.

With your 1-7, use the 55s for cheap reduced range practice, it wont hurt anything but I believe you'll save a few bucks.

Heck I even shoot cast 55s in my WOA for practice. That allows more practice for less bucks. And unless you shoot them at hyper velocities, they are fairly accurate.

[P-990]

I agree with Kraigwy on this one.

I load and shoot 52gr Hornady and Nosler HPBTs for my 1-7" AR-15. Not a problem yet. I run them a bit under max-charge and just shoot. Any day I can shoot 10 rounds at a reduced target and only drop 2 points, I know the rifle/bullet combo is fine.

Also, I believe Magnum primers are even recommended in some instances for 748. It's what I use for my 52gr loads; 748 and a CCI-450 SR Magnum primer.

[Unclenick]

I'll echo the last two posts. I have a 7 1/2" twist barrel on my Compass Lake gun. It thinks the little flat base 53 grain Sierra's are just dandy to about 200 yards (if the wind isn't too high). I usually run them with moderate loads of IMR4198 or Reloader 10X. I assume H4198 would work, too. Around 3000 fps to keep from upsetting the little darlings with all that spin. The last two loads on my books were 20.5 grains of IMR 4198, and 22.4 grains of Reloader 10X in Winchester cases, and with my usual blatant disregard for slamfires (which I'm convinced are mainly due to high primers), Federal 205M primers; bullets seated to 2.230" (easy to remember).