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9/19/2017 7:27:10 PM
Posted: 5/15/2003 8:41:31 PM EDT
Will these two rounds work in a 1:9 twist rifle?
Link Posted: 5/15/2003 10:18:30 PM EDT
77gr won't. 75gr will work in 1:9 20" barrels (tight groups) at least to 100 yards (I haven't had a chance to try beyond that yet). 75gr will work in 1:9 14.5" to 50 yards at least. I was having problems at 100 yards, but it could have been the copper buildup.
Link Posted: 5/16/2003 12:13:51 AM EDT
Look for some of the posts from about the last two months.
Link Posted: 5/16/2003 12:22:38 AM EDT
Forest are you speaking from experience? The 77 is a shorter bullet than the 75 and thus requires less RPMs to stabilize it than the 75 grain.
Link Posted: 5/16/2003 6:35:23 AM EDT
75 grainers won't work in my 1:9" 20" barrel. 1:9" guns seem to be hit or miss with bullets of this size, and yes, it is correct that bullet length is more important than bullet length. I would recommend buying a box and trying them out. I did, and although I was disappointed in the results, I wouldn't have learned any other way. 69 grain Sierra Match King bullets are a decent alternative for those of us who can't shoot the 75's.
Link Posted: 5/16/2003 6:56:15 AM EDT
Depends how fast they're going. A longer barrel will definitely help.
Link Posted: 5/16/2003 7:07:58 AM EDT
[Last Edit: 5/16/2003 8:38:14 AM EDT by mr_wilson]
Ditto, barrel length and velocity are the keys here. Listing your barrel length would help, whywork. FWIW, I shoot nuthin but 77SMKs outta my 24" 1/9 CR-6724, but their cookin along at max velocity, (2850fps range). This same load ain't worth squat in either if my 1/9 16" M4s, RRA or Colt. But they did shoot knots in my RRA DCM/CMP 20" 1/8. Mike edited to correct velocity
Link Posted: 5/16/2003 7:44:51 AM EDT
[Last Edit: 5/16/2003 7:45:29 AM EDT by 1911ar-15]
Just try them yourself. They work fine for some people and not so good for others. In my 20" Bushie I get 2650 fps (in 40-degree weather) with blue box Blach Hills 75gr, and get fine groups (and nice round holes) at 200 yds. Some people report keyholing with the same bullet and 20" barrels at 100 yds. If you have a 16" your chances of stability are fairly small, but you'd still have a chance. Just buy a box and find out for sure.
Link Posted: 5/16/2003 8:08:41 AM EDT
Originally Posted By DevL: Forest are you speaking from experience?
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Not my personal as I don't have access to 77gr rounds in the area. A contributer to my site tried them in his 16" and mailed me the results. IIRC his MV was also lower than the MV of the 75gr that I tried. As always YMMV.
Link Posted: 5/16/2003 2:15:12 PM EDT
Sorry that I didn't give more info. I have a new Colt MT6700 20" A3. I have just gone to the range for my first day of breaking the gun in. I did take the recommendations of this board and bought many different makes of bullets to try out. Instead of buying 1000 rounds of one type I bought about 200 rounds of 5 brands to try. 3 or them are 55 grain one is 50 and the other is 60 if I remember right. When I purchased the rifle most recommended the 1:9 twist barrel because it will shoot the most veriaty (I know that is spelled wrong it just doesn't look right) of rounds. I would like to know the biggest round it will shoot properly? I was reading another post about the 75 and the 77 grain bullets which seem to be as big as they get for the .223. Thanks
Link Posted: 5/19/2003 3:19:42 AM EDT
Originally Posted By whywork40: I would like to know the biggest round it will shoot properly? I was reading another post about the 75 and the 77 grain bullets which seem to be as big as they get for the .223. Thanks
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Suspect 69grn. bullets are the heaviest ya can go, with the 20" ya MIGHT get the 75s to shoot, you'll just have to try them in your rifle, to see. FWIW hope to hear some good news on the BH 100 grain bullet soon and alot of HP shooters use the 80 and 90 grainers from the 600 yard line, but all have a faster twisted barrel than 1/9. Mike
Link Posted: 5/19/2003 5:25:23 AM EDT
I have shot the 75 grain in a 16in 1/9 and got very good results. Try it and see if they work for you. Some of the confusion seems to be that people naturally expect match grade accuracy from a 1/9. I tested for accuracy to see if the 75 grain loads would shoot as accurate as a milspec load. I got much better accuracy in my rifle than the milspec loads produced. I'm not a fan of the heavier loads so I'm not recommending them but if you want to shoot them then try them and see if you can live with whatever accuracy you get from your rifle.
Link Posted: 5/21/2003 4:25:54 PM EDT
i've shot 77gr. federal match grades in my 24" bushmaster and they shoot pretty damn good. i've had no problems with feeding at all. i like them and will continue to shoot them as long as they give me the accuracy i like.
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