.300 Blk For PA Deer Season

Nicholas C
by Nicholas C

My friend Brian Miller sent this to me.

Making an Ar-15 legal for Pennsylvania deer season.

I have wanted to use my 16″ M4 AR in deer season. Unfortunately in my home state of Pa, in stock configuration, that is not legal. So I decided to remove the gasblock and gas tube, and machine a ring out of aluminum to block the gas port.

I decided to use my Vortex Viper PST 2.5x10x44 in a QD Larue mount. This is the optic I am planning on using for open class in 3-gun next year. The scope might be bordering on overkill, but it is what I had laying around. I do not pick up the front sight post in the scope when it is mounted.

It would not matter because the front post is coming off anyhow.

I have always wondered approximately how much velocity is lost cycling the action, so I decided to chrono my shots before and after my gas system was blocked.

Now I realize this small test is not terribly scientific, but the results were interesting to me.

Cute little devils aren’t they.

I used hand loaded ammo with the charges weighed exactly the same on my digital scale. I shot the groups at 50 yards in the same environmental conditions.

5 rounds 110 grain Vmax with gas system intact:
High 2267 fps
Low 2251 fps
Average 2257 fps
ES 16
SD 6

Group size at 50 Yards

5 rounds of 110 vmax with the gas system blocked:
High 2291
Low 2255
Average 2267
ES 36
SD 13
Group size:

When cycling the action I racked the bolt and pushed on the bolt catch to lock back the bolt on each round. Then dropped the bolt by hitting the catch. I thought it would be the most consistent method. I am not really sure what is going on here relative to the group size. Both groups felt the same when the shots broke, I called no flyers in either group. I have heard rounds fired out of an AR where the bolt was dropped manually was not as accurate, but I had always dismissed it. Maybe I should reevaluate that thought. Shooting the rifle with and without the gas system did feel different to me. Shooting it semi, the shot would break and the crosshairs would rise then drop back on target. Without a gas system, they would rise and not really settle for me. This is attributed to the mass of the bolt carrier and buffer slamming back into battery. I am looking forward to trying this rifle out this year. Running the data through my Strelock app on my phone, I think it will work fine for digging them out of the brush on my property.

Nicholas C
Nicholas C

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  • Bmiller Bmiller on Dec 08, 2015

    I have an update. I was able to take a doe with the rifle. It was completely relaxed, grazing, it was looking at me, but didn't seem to care. That is the way I prefer to take them, I have shot deer that were pushed and stressed out and they seem much stronger tasting to my taste buds. The shot was approximately 150 yards quartering toward me. With this rifle and load, it has a 50, 150 zero. I took the shot. When the bullet hit, it sounded like a water balloon popping. It juked down and ran off into the woods. It was recovered about 20 to 25 yards inside the woods. Not much of a blood trail, but good enough. I hit it between the neck and shoulder where I was aiming. It destroyed the lungs and the top of the heart. About a nickel sized entrance hole, no exit. I did not recover the bullet. My friend who processed the deer thought it wasted less that a cup of meat. All in all, I think it is a great meat gun for deer. Does it hit them with as much authority as my .300 ultra mag? No, but it doesn't have 6" exit holes either. I really enjoyed hunting with the rifle. I put my Vtac sling on it, and that made getting in and out of my ladder stand very easy. (I am NOT fond of heights!). I had the rifle laying around and always wanted to take a deer with it. I would love to see Pa make semiauto rifles legal for hunting, but I am not holding my breath. I also found I got normal groups with racking the charge handle and just letting it drop, rather than using the bolt catch. I am still not sure what is going on there. I do not think this is the ultimate deer rifle, but it served me well and sure was fun! I think my next project is going to be a Savage short action in 6.5 Creedmoore in a Ar-like chassis coming in around 6.5 to 7 pounds in weight. That just might be the perfect rifle.

  • JBC JBC on Dec 08, 2015

    Stop being different bmiller, people are about to fight!!