View Full Version : Twist Rate for Self-Defence AR-15

05-22-2008, 08:03 PM
I am looking to buy an Olympic Arms M4 Style AR-15 for home and property defence. The rifle has a 1 in 9" twist rate. Is this the proper twist for 55gr. bullets? I want to use the 55's because alot of bulk and defence ammo is in this weight.

Also, what mags, ammo, accessories, etc. do you all prefer? Do you know of any good related web sites?



05-23-2008, 12:17 AM
Yes that is the correct twist rate. You will need the 1 in 7 twist barrel if you want to accurately shoot the heavier 65 to 70 grain and up bullets. 55 grain is the most prevailent so I think you got the right barrel.

05-23-2008, 12:21 AM
55 grainers will stabilize well in bbls with a slow twist of 1/14".

www.ar15.com will get you more info than you will ever need.

Are you Scottish?


05-24-2008, 05:20 PM
First of all kudos on your weapon choice - as a former Marine and Gulf War vet, my military version of the "evil black rifle" (EBR) never let me down.

I too suggest spending some quality time combing through the forums at www.ar15.com - there is more information there about ar-15 accessories, ammo, and such then you will be able to absorb in a month.

One suggestion, take a peek at Rock River Arms (www.rockriverarms.com) - they carry some really nice EBRs for a good price. Remember that military surplus ammo is inexpensive, but not as accurate (not really a huge issue for home defense - since most of the time you won't be engaging from 300 yards, but an inch or two off target may be the difference between a target DRT (dead right there) or several hours of chasing your wounded dinner through the woods until it bleeds out) - I'd keep a few rounds of the better ammo around tho if you plan on using your new tool for hunting as well as keeping the bad guys out of your pantry.

05-25-2008, 05:05 AM
My Bushmaster has the 1 in 9 twist rate as a compromise for the 55's i mostly use and the 62 grain green tips I also have a stored supply of.

I prefer the 55's due to the original yaw and disintergration aspects of the round in living targets. Since I have some heavier ammo in the house I decided not to go with the original 1 in 12 inch twist rate my M16A1 had for the military 55 grain ball ammo I was issued.

My current rifle is a 16" carbine. I hope to get a 20 inch A4 style rifle model as well. It too will have the 1 in 9 rate to compromise with my ammo options.

You are doing good my friend. :)

06-04-2008, 10:06 PM
+1 for Rock River Arms, or Bushmaster over Olympic. I would recommend a chrome lined barrel and either 1/7 or 1/9 twist rate will suffice. Magpul "PMAGS" have an excellent reputation and have proven themselves to be superior to standard AR15 magazine's. The cheapest place I've found them is aimsurplus.com for $14.21 shipped. Most places have them for the same price, but shipping is extra. With Aim, you can order one or two mags at a time and not get hammered by shipping costs.