22 Cal. Barrel rate of twist

easygo6

This may be a common question that has been discussed before. I am buying a 22 cal (223 Rem/5.56) rifle, a RRA AR-type. I do not want to launch bullets heavier than 65-68 grains.

I known a rate of twist can be too slow to stabilize long bullets. My question is..can the rate of twist be too fast and de-stablize shorter bullets?

The rifle I am buying is available in a 1:8 twist or a 1:12 twist. For varmint shooting where I want velocity over bullet weight(less intrusion of the bullet into the case)what rate of twist is recommended. If the 1:8 twist will not de-stabilize the shorter bullets I would be willing to go that route.

THANKS

SEMPER FI

richbug

Some hollowpoints like Speer TNT's that are prefragmented will explode upon leaving the barrel because of the the high rate of twist. I personally witnesed this in an AR loaded with my handloads. (50 grain TNT at 3400fps)with a 1in 7 twist. the bullets didn't hit the target at 25 yards and there was a funny cloud upon firing.

My border collie is smarter than your honor student.

easygo6

nononsense posted an informative response on 12/26/2003, from A Shilen barrel site.

What I am looking for is can a twist be TOO fast. richbug's response to this posting is sobering, but I do not expect to be firing such light weight of 'pre-fragmented' bullets.

Any help would be greatly appreciated.

SEMPER FI

temblor

For the shooting you have described and the bullet weights you mentioned the 1x8" is best for you, although a 1x9" would probably do the range of weights you want to shoot better if you could get one in that twist. -- The 1x12" will generally stabilize the very light bullets on up to about 60grs. Some bullets are made longer,etc. and will sometimes shoot ok, and length of barrel and velocity will sometimes make up the difference and work too. The 1x8" will stabilize the heavier bullets you mentioned and maybe a little heavier. The faster twist will work on the varmit weight bullets also, but you just need to use a bullet that doesn't have a very fragile jacket like those mentioned above and others so they will stay together at the increased RPMs. Most reloading manuals will tell you what velocity,etc. that a particular bullet is recomended for use at. The Speer TNT and the Hornady SXSP are two that come to mind that will come apart because of jacket design, but are great on varmits in a gun with the right twist and at the recomended velocity. -- You can't "over stabilize" a bullet with a fast barrel twist rate, but you can tear them apart if you use the wrong type of bullet going to fast or spin them to fast. Just use a something like a Hornady v-max or a Nosler Ballistic Tip that will stay together. -- Good Luck...[8D]

1KYDSTR

Temblor gives a really good reply here. I would like to add that in addition to "blowing up" a bullet by overstabilization, there is the risk of fouling the throat and early part of the barrel by "stripping". This is a phenomena that occurs when a bullet sheds a portion of its' copper jacket because of either too fast a twist or improper use of a gain twist barrel; this generaly happens in the throat area as the bullet, once it has made it into the barrel it is being forced concentric by the rifling. A one in seven twist rate at that velocity will impart about 310,000 rpm; that is definately spinning quick!! If the light bullet is being introduced into the throat at this kind of speed, its' light mass in conjunction with ultra high velocity will "strip" copper until the rifling forces it to stabilize. Also, unless the bullet is PERFECTLY concentric, at these high RPM's, the center of mass is constantly trying to fight the rifling and the bullet will not dampen until about 200 or so yards...which can make things a bit confusing when trying to determin accuracy at 100 yards. Confused yrt? Hope this din't add too much to the confusion and makes SOME kind of sense.

"When I cease learning...I'm dead"(Me)
"Power corrupts...Absolute power corrupts absolutely"(Descartes?)
"History is written by winners"(Patton)
"You get a lot farther with a kind word and a gun than you do with a kind word alone!"(Al Capone)
"There is nothing lower than the human race...except the French" (Samuel Clemens)

easygo6

THANK YOU SO MUCH! I consider myself knowledeable, but not an expert on all matters. I love this forum!

1KYDSTR and temblor, your responses were on target. The responses also pass the 'smell test'. Thank you so much!

easygo6/Montana1 (GB)/Brad



SEMPER FI