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Posted: 3/20/2015 8:34:02 PM EDT
| i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? |
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i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? 100 yds for an ACOG. Zero with whatever ammo you will mostly shoot. I tend to zero my sights and optics with 5.56 Usually M855 but considering the whole ATF thing I zeroed with XM193 a couple weeks ago. But just use whatever you will mostly shoot. |
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i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? The RCO is calibrated for the M4 ( 14.5 inch ) barrel. I would go w/ 50/200 zero , your 20 inch barrel shouldn't effect zero but, the BDC may be off by a bit. |
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The RCO is calibrated for the M4 ( 14.5 inch ) barrel. I would go w/ 50/200 zero , your 20 inch barrel shouldn't effect zero but, the BDC may be off by a bit. Quoted:
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i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? The RCO is calibrated for the M4 ( 14.5 inch ) barrel. I would go w/ 50/200 zero , your 20 inch barrel shouldn't effect zero but, the BDC may be off by a bit. he stated he has the A4 model. |
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he stated he has the A4 model. Quoted:
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i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? The RCO is calibrated for the M4 ( 14.5 inch ) barrel. I would go w/ 50/200 zero , your 20 inch barrel shouldn't effect zero but, the BDC may be off by a bit. he stated he has the A4 model. Oops! my bad, I read it as M4.  . Still would go with a 50/200 zero , and the flavor of pill you plan to shoot the most.
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Oops! my bad, I read it as M4. . Still would go with a 50/200 zero , and the flavor of pill you plan to shoot the most.Quoted:
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i have a TA31 RCO A4 and a 20" PSA premium upper, What range and ammo do i use to zero this optic? Im guessing 100 yards with M855? The RCO is calibrated for the M4 ( 14.5 inch ) barrel. I would go w/ 50/200 zero , your 20 inch barrel shouldn't effect zero but, the BDC may be off by a bit. he stated he has the A4 model. Oops! my bad, I read it as M4. . Still would go with a 50/200 zero , and the flavor of pill you plan to shoot the most.The optic is designed to be zeroed at 100 meters. |
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I hear 36yd poa=poi will get you a good 300yd Z. Idea behind that is it gives you the overall flatest trajectory. Takes a bit of compensation out of it.
Have tried it to a limited degree, need to do some confirming with other AR's though. An experienced buddy uses it and has so far been able to hold dead center on yard pests over a varied range. We've only tested this with irons and red dot optics so far. The theory behind it should be still 100% true with that Acog, but I can't confirm. |
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M855 is what the velocity and ballistic coefficient based on.
Out to 300 meters, M193 is pretty much spot on. It starts to change there, but still accurate enough out to 500m. The ACOG isn't designed to be a precision optic anyway. The TA31F is pretty much a hybrid reticle that splits the difference between a RCO-M4 and RCO-A4. More correctly, it splits the difference between the BDC of a 14.5" barrel and a 20" barrel firing a round with the ballistic characteristics of M855. If you want to be 'correct' for a 20" A4 rifle, find yourself a TA31RCO-A4. The BDC will match perfectly using M855, and will be damn close with M193 out to 300+ meters. You would be 'damn good enough' with a TA31F out to 300m with either round from the 20" rifle. |
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M855 is what the velocity and ballistic coefficient based on. Out to 300 meters, M193 is pretty much spot on. It starts to change there, but still accurate enough out to 500m. The ACOG isn't designed to be a precision optic anyway. The TA31F is pretty much a hybrid reticle that splits the difference between a RCO-M4 and RCO-A4. More correctly, it splits the difference between the BDC of a 14.5" barrel and a 20" barrel firing a round with the ballistic characteristics of M855. If you want to be 'correct' for a 20" A4 rifle, find yourself a TA31RCO-A4. The BDC will match perfectly using M855, and will be damn close with M193 out to 300+ meters. You would be 'damn good enough' with a TA31F out to 300m with either round from the 20" rifle. Thanks I do have a ta31 rco a4 as this is the only "correct" acog for a 20" rifle. |
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The RCOA4 is for a 20" firing M855.
The RCOM4 is for a 14.5" firing M855. The TAO1NSN is for a 14.5" firing M855. The TA31F splits the difference in barrels for M855. At 25m zero your A4 using the 300m line and fire at 100m to confirm and make fine adjustments. |
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M855 is what the velocity and ballistic coefficient based on. Out to 300 meters, M193 is pretty much spot on. It starts to change there, but still accurate enough out to 500m. The ACOG isn't designed to be a precision optic anyway. The TA31F is pretty much a hybrid reticle that splits the difference between a RCO-M4 and RCO-A4. More correctly, it splits the difference between the BDC of a 14.5" barrel and a 20" barrel firing a round with the ballistic characteristics of M855. If you want to be 'correct' for a 20" A4 rifle, find yourself a TA31RCO-A4. The BDC will match perfectly using M855, and will be damn close with M193 out to 300+ meters. You would be 'damn good enough' with a TA31F out to 300m with either round from the 20" rifle. Thanks I do have a ta31 rco a4 as this is the only "correct" acog for a 20" rifle. Fair enough. I guess because your thread title was TA31 I glazed over where you mentioned you had an RCO-A4. You're all set, then. |
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