75 gr. through a 1:9 Twist

[FUPAGUNT]

Just picked up some TAP 75 gr. and was wondering how it would shoot through a 1:9 twist barrel? I will be using it with a Armalite AR with a 16" heavy barrel if that makes a difference..

 

[Clay]

When I shot 75 or 77 through my 1:9, it's a good 2-3" high, yaws at times and is not as accurate as 55 or 62.....

I didmt get a PM from you, just saw u had asked me.

 

[gunnerxxx]

I have to agree, the 1:9 is designed around the lighter bullets. accuracy will be lost.

 

[SAWMAN]

The contour of the bbl is a (NF)no factor. Neither is the weight except it will make a difference as to the bullets speed. Which will make an even smaller difference in the bullets stability. The bullets speed difference in several hundred FPS will make a difference though. The big factor is the bbls twist rate. I tell people that "generally" the max weight for a 1:9 twist is the 62's.

Remember also that the weight of the bullet does not make this difference. It is the bullets length,contour,and design/makeup. Generally,the more lead the bullet has the more stable for the caliber and weight(length). Contributing factors in this area are the Partitions,boattail/flatbase,the poly tips,and especially the solid coppers. All this will effect the bullets length to caliber ratio.

Sooooooo..... I say that the max bullet weight for a 1:9 twist bbl is the 62's. You might gain a super small amount of BC with the heavier bullets but the limited velocity will bring the "goods" down a little. The difference between the 62's and the 75's is so small and easily mitigated by your scopes setting that I do not even consider these somewhat heavier bullets. ESPECIALLY for hunting. Basically....for hunting, heavier is not always better. Bullet makeup and shot placement are the "gotta haves" here.

All this is why I say...with the 223/5.56 the 1:7 twist bbls are the king. They will shoot any bullet. Remember that their is no such thing as "over-stabilization". --- SAWMAN

 

[Gravity3694]

I would test it. 75gr is at the upper limit for 1:7, even some 77grs may work. You already bought the box, so your kinda stuck with it.

Over-stabilization can spin a bullet apart. If you have a 1:7, generally a 36 or even 40 grain will spin apart.

 

[SAWMAN]

I have shot some 40gr NosBalTips out of my 24" Bushmaster at 3700+fps. No problem....unless they hit a blade of grass en route to the target. Upon impact with a woodchuck you become a charter member of the Seekers of the Red Mist society.

I remember when Hornady came out with their 50gr SX(super explosive). They warned about shooting them in the 1:10 twist Mini 14's. Never had a problem with that either.

My belief is, it is not the rotational velocity that pulls a bullet apart(even the above 40gr at 380,571rpm's)it is when it impacts even the slightest object and starts to mushroom(no matter how slight)or starts to pitch or yaw. Then.....centrifugal force is a MoFo. --- SAWMAN

 

[oneshot]

One shot drop with Rem. 700 PSS1/9 on a white tail at 630 yds with a H-Amax 75 gr. I guess some 1/9 will shot, that is just about all I shot in it. Just my 2 cents jj

 

[Hunkyfish]

One shot drop with Rem. 700 PSS1/9 on a white tail at 630 yds with a H-Amax 75 gr. I guess some 1/9 will shot, that is just about all I shot in it. Just my 2 cents jj

How long is your barrel oneshot?

 

[SAWMAN]

YOU SIR....not only have an exceptional rifle but indeed you are an exceptional shooter.

May I please ask. At what velocity was the bullet going out of the bbl ?? What velocity was it going when it got to the deer ?? What did you have the rifle zero'ed at ?? How high above the deer did you have to hold ?? Was there any cross wind ?? If so how much into the wind did you have to hold ?? Full value,half value,etc.

I love talking ballistics and would like to hear the info on this shot. Thank you. --- SAWMAN

 

[Little Jack]

YOU SIR....not only have an exceptional rifle but indeed you are an exceptional shooter.

May I please ask. At what velocity was the bullet going out of the bbl ?? What velocity was it going when it got to the deer ?? What did you have the rifle zero'ed at ?? How high above the deer did you have to hold ?? Was there any cross wind ?? If so how much into the wind did you have to hold ?? Full value,half value,etc.

I love talking ballistics and would like to hear the info on this shot. Thank you. --- SAWMAN

Holy crap! Maybe he just got lucky? I forget what color the pants were I put on this morning.... wait.... they're black.:smile:

 

[oneshot]

Let me see if I can answer this in order velocity checked with con. 2700 ft,, deer wouldn't tell,, zero'ed at 100 yd. didn't hold over,,, no cross wind,, bl. 26'', had witnesses. Didn' always have witness, but this was done on more then one time, the 200 plus deer nevery would tell us what the velocity was when it got to them,. We did work this out on a bast. chat. before hand and then went out checked it out to 800 yds. made up a cht. and post it with the gun. then when a deer came out we laser him for dist. then would dail in the scope.then worked for good shot placement, the bullet with a front chest shot would go clean through on a large size doe. we didi this with our 308 also. the avg. shot was from 350 to 500 yds. the field we where on was 440 across and 840 long. I didn't make it but my shooting buddy did one at 800 yd with 308. Just my 25 cents jj