For the benefit of all the IPSC/3-gun newbies, I'm starting this thread where experienced competitors can post photos and descriptions of their DEDICATED match rifles. I know a lot of us also use standard rifles quite successfully in these matches, but I'd like to try keeping this thread limited to dedicated rifles only (Open, Standard or Tactical division). Here is mine:
The upper was supplied by Model 1 Sales, and the lower is a Bushmaster with JP trigger. Here is a detailed description of the design choices I made and the challenges I encountered during the build.
The barrel is Model 1's standard 20" stainless 1/9 "preban" (as it was then). You can use any barrel length you like in IPSC - I chose 20". More than 20" is unwieldy. 16" is OK if you can be sure your ammo will always make at least "minor" power factor (need to make at least 2728fps at the muzzle with a 55gr bullet). Perhaps more importantly, I like the extra punch of the longer barrel to knock down steel targets reliably at longer ranges. The trend now appears to be towards 18" barrels. My barrel came with a regular flash hider, which I unscrewed and replaced with a pre-ban threaded JP "Benny Cooley" compensater/muzzle brake; this brake works well, and complies with IPSC Standard division rules on overall size (as I recall, 1"x3" max). I used an A1 lock washer and red Loctite to index the brake, rather than a peel/crush washer, as I did not want to cause any accuracy-robbing stress around the muzzle area (though this may or may not be significant).
A free-float handguard is a useful addition for IPSC, as you often find yourself resting the forend against range props (walls, barrels etc.). My aluminum FF tube did get uncomfortably hot during extended courses of fire, though. I fixed this easily by wrapping the tube with Paracord, and this solution works great. Others have used ventilation slots cut in the aluminum tube (I don't know how well these work) or a carbon fiber tube (which would also reduce the weight, if you wanted that). I believe DPMS also offers a plastic sleeve to slide over an aluminum FF tube. I like the Paracord approach myself, and would do the same again on future rifles.
Because it has a heavy barrel and aluminum FF tube, this rifle is much heavier than my M4, and the balance is much more towards the muzzle. However, in a purely competitive rifle that is predominantly shot against the clock at 50-400yard distances, the extra weight is acceptable... I am giving up some speed of handling for stability, recoil recovery and heat tolerance. Of course, if I have to carry the rifle for any distance, I'll reach for my M4 every time
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I shoot primarily with iron sights (again, to comply with IPSC Standard rules). The rear sight is a DPMS unit; it works well, though I had to use a Dremel to lengthen an internal slot so that it would adjust up to 600M... this is a known issue with this particular sight. The front sight is a removable M&A sight base (available from Model 1 too, as I recall) into which I installed a National Match front sight post - this post is narrower than the standard A2 unit and so gives a more refined sight picture. The front sight base mounts on the Model 1 dovetail gas block, and here is where I found the only problem with this upper: the gas block size is not a good match for the front sight base... the combination of these parts puts the front sight maybe 1/4" too high, and it's impossible to get the post low enough to zero the rifle. I fixed this by machining away unwanted material at the top of the front sight base, and then using a tap to extend the threads down deep enough to correctly zero the post. This worked OK for me, but was a bit of a hassle (the correct tap is difficult to find) - in hindsight, I should have ordered the upper with a regular GI fixed front sight base (as I shoot Standard division almost exclusively). Alternatively, if you prefer a removable front sight, you could consult with your vendor to choose a gas block and front sight combination that will be closer to the correct height. Of course, this is unimportant if you will only be using optics.
I have built two rifles using Model 1 kits, and can honestly say that reliability has been perfect for both. And I do mean perfect; not one malfunction since they were built. The IPSC rifle has had several thousand rounds through it, and it never lets me down (ooops, now I've done it
). If you are going with a 16" barrel and carbine gas system, I'd suggest using an extra-power extractor spring and an H-buffer for improved reliability.
The only other mod I recommend for IPSC is to add a Johnson RediMag, which makes for really fast mag changes (particularly when prone). Also, you will notice in the photo of my rifle that I use 30-round GI magazines with rubber MagPuls turned "sideways" on the base... I do this to avoid cutting my hand during reloads and so that the mag can act as a steady monopod for prone shooting - a bipod is not allowed in Standard division.