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Posted: 6/2/2017 11:48:50 AM EDT
Without having to go through countless threads what are the two most common ACOGs that are used on A4s? I know the TA31RCO-A4 is the current unit but what was the one it replaced(the cheaper model )?
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If you're talking about what ACOG is standard issue for USMC M16A4s, that is and only ever has been the TA31RCO-A4CP. The TA31RCO-M4CP is USMC issue for M4s. The TA31RCO-M150CP is the what the Army uses for M4s, though there is no standard issue optic in the Army. The -M150 is the same as the -M4 (for M855 out of a 14.5" 1/7 barrel), but comes with caps for both lenses. Contrary to popular misconception, the -M150 is not calibrated as a compromise between 14.5" and 20" barrels.
HunterKiller86 is right; outside of those three models, it's not immediately clear what barrel length, twist rate, and bullet weight the various models are calibrated for. |
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I'm in the same boat. Trying to outfit an A4 clone and I found an m150 for $1100 to my door which seems to be a pretty good price. Couple hundred bucks for the RCOA4 so trying to pick. I've got an M4 clone was well I could swap between. |
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Might be true, but if I'm gonna spend the money for an ACOG, I'd like to get the one that's correct for the barrel length. If you don't want to shoot that way with that ammo, then get the reticle you want. The BDC isn't gonna match up. You'll need to figure it out by discovery learning or a ballistics calculator and subtension data. |
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As long as you plan to shoot M855 and your targets will be in meters, you'll be fine. If you don't want to shoot that way with that ammo, then get the reticle you want. The BDC isn't gonna match up. You'll need to figure it out by discovery learning or a ballistics calculator and subtension data. M193 and similar rounds often track nearly identical to M855 out to 500 meters in my experience |
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I understand what you're trying to convey but that isn't entirely correct. M193 and similar rounds often track nearly identical to M855 out to 500 meters in my experience I used the velocity data here and Federal's Ballistic Calculator. Consider the M855 round from a 14.5 inch barrel is about 2800fps. An M193 fired from a 14.5" barrel is a little faster at about 2900 fps. At 500 yards, the difference is about half an MOA. An M193 fired from a 16" barrel is faster at about 3100 fps. At 500 yards, the difference is about 2.2 MOA, or 11 inches. An M193 fired from a 20" barrel is significantly faster at about 3200 fps. At 500 yards, the difference is about 3.7 MOA, or 18 inches. Most ranges in the US are demarcated in yards. That's an additional ~10% variance to consider. I'm not saying don't buy an ACOG. I have one and love it. It's my go-to optic. I use it on ranges that are measured out in yards. I'm saying a guy should understand how the thing works before plunking down north of a thousand dollars. It ain't magical and won't break the laws of physics to keep your rounds on target. For most average citizen shooters, it requires some discovery learning based on a shooter's ammo, barrel length, and range. |
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Once zeroed, most shooters will never know a difference between any model on a given weapon. These are not target scopes. |
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