Shooting the AR15 22LR Conversion Kits

[barnetmill]

I certainly was pleasantly surprised as I bought it mostly for the stated subsonic velocity for use with a suppressed bolt action rifle.

Out of curiosity, In rifle barrels was the CCI SV target 'subsonic'. As you stated for high volume use the lead outside wax lubricated bullets will require cleaning at a lower round count in a blow back rifle.
Some of the 50 yard .22 bench rest rifle people say they never clean their rifles. They ammo that they shoot from what I have seen often has either wax or a grease on the bullets. The guns are bolt actions and so a tight chamber is more readily fed a round.

[TD1886]

Larry let's address the Browing rounds not firing. I rechambered them so the firing pin would impact another spot on the rim and still no bang. Also I fired more Browining after that inaddition to other waxed bullets and they all went bang. I shoot a lot of 22LR and as lately quality control has gone downhill. It was the three Browning rounds that weren't good. Maybe I'll pull the bullets and see what I find inside.

I didn't miss the obvious. If you read what I mentioned previously if that conversion unit misaligns even the slightess amount it can start the bullet crooked into the bore. So if you have a crooked bore in the bore which twist is going to amplify that the most, the 12 twist, the 9, the 8, or the 7? BINGO! Yup you got it right the 7 twist.

I'm not finished yet and I still have more tricks up my sleeve to get these conversion units shooting better in all twists.

[TD1886]

Okay Larry let's get a little more serious. First off I removed my unit from the gun and I was shocked at how clean it was. No wax, no nothing on the breech face the cartridge rim is up against.

Okay I measure the unit's cartridge (by that I mean the part that goes into the chamber of the rifle) and a fired cartridge. Here are the figures

Fired cartridge Device Cartridge Difference

Ahead of ext. groove .375 .373 .002
At the shoulder .3563 .3535 .0028

I couldn't measure the length to the datum line on the shoulder so I assume it has tolerance in it too.

Now do you expect something fitting like that is going to give you target bolt rifle accuracy? I don't. Who's to know between each shot if flip flops around and maybe not being in the same position all the time is were the fliers come from amplified by the 7 twist?

Only one way to do this and I'm not going to put the money out for, but that is have a 7 twist barrel made for a 22LR with a match chamber on a bolt action. Now if I could come by a 20 inch 5.56 barrel I would be willing to fit it to a junker 22LR bolt gun I have, even though the bore would be larger. Guess I would have to swage up the ammo in that case.

Your default is the 7 twist, it's not mine.

[Larry Gibson]

Out of curiosity, In rifle barrels was the CCI SV target 'subsonic'. As you stated for high volume use the lead outside wax lubricated bullets will require cleaning at a lower round count in a blow back rifle.
Some of the 50 yard .22 bench rest rifle people say they never clean their rifles. They ammo that they shoot from what I have seen often has either wax or a grease on the bullets. The guns are bolt actions and so a tight chamber is more readily fed a round.

Yes, the CCI SV Target was indeed subsonic. I chronographed it out of both the AR/M261 and my Ruger 10/22, both suppressed. With the suppressor there was no muzzle blast to trigger a close start screen so the start screen of the Oehler M35P was just a couple inches in front of the suppressor. That effectively measures the muzzle velocity within a couple fps. The average velocity out of the 18" 10/22 barrel ran right at 1050 fps and out of the 20" AR barrel right at 1055 fps. There is no "snap" of sonic crack in front of the suppressor so, as I mentioned, all one hears is the action functioning and the whop of the bullet striking the target. The use of outside lubed lead bullets in blowback actions does indeed require cleaning as buildup of the powder/lube residue can lead to misfires from the bolt not fully closing. This also applies to my Browning Challenger pistol. In My Colt Ace M1911 conversion the floating chamber will lead/powder foul up within 50 - 100 rounds of lead lubed 22LR ammunition and cease to function. With copper plated 22LR ammunition if will not lead/powder foul up and will continue functioning. However, I do clean it after every use.

As for my bolt action rifles, I shoot 100 yard 22LR BR matches with my Remington M37 Target rifle. I clean it once a year maybe. Maybe, but only if the groups open [my score falls off not due to me or the wind]. I only shoot the higher end target ammunition in it, usually Lapua Midas+. I shoot a mix of different kinds of ammunition in my Remington M504 w/o any problems. I usually will run a dry patch through the bore when switching ammo is all. Same goes for my Norinco M98 trainer. With my old single shot 22LR rifle I shoot shorts, longs and long rifle 22 ammo through it and don't remember the last time it was cleaned.

Note; "cleaning" to me refers to the inter of the action and the bore. I keep the exterior of all my firearms clean and lightly oiled.

[Larry Gibson]

TD1886

Not having any Browning 22LR ammunition or having ever fired any I cannot speak to the quality or lack thereof.

As to the lack of any residue/fouling in the action of your device, apparently your experience varies greatly from mine.

In an earlier post of mine in this thread or perhaps the other thread I stated the possibility of the long throat of the devices and the possibility of damage to the bullet was likely. That, of course, was just an opining based on the probability of some misalignment. However, the continuously demonstrated decrease in accuracy as the twist gets faster is ample proof the increased centrifugal force is acting more on whatever those damages (imbalances) are. It is not a "default", it is proven fact.

As I said, doing what you are doing you may very well find a combination of modifications and ammunition selection that may give adequate accuracy out of your 7" twist AR for your needs. Keep at it, who knows. If you have the money and the desire to build a 7" twist 5.56 barreled bolt action 22LR then be my guest. It will be interesting to the results. I'd venture the accuracy may improve because the bullets probably wouldn't get damaged as much because of the standard chamber, ergo the centrifugal force of the increased RPM (over that of a 12" twist barrel) won't have as much imbalance to act on.

However, I've no intention on trying to turn any of my ARs into target/match rifles using 22LR in 5.56 barrels. The M261 device in my 12" twist AR with several different brand/types of 22LR ammunition suits my needs for it very nicely. Thus, I'm a happy camper with it and, like they say.....if it ain't broke, don't fix it.

[TD1886]

As I said, doing what you are doing you may very well find a combination of modifications and ammunition selection that may give adequate accuracy out of your 7" twist AR for your needs.

Larry I've already demostrated that. I said my 7 twist HBAR is minute of squirrel at 50 yards. I'm just having fun with it. I have a bolt 22LR that can out shoot most the high dollar target 22LR's. Off topic a wee bit, but still on rimfires, I've said for years that the 22 Magnum could be made extremely accurate and I've proven that, to myself, with a target AR15 in that caliber. I got a special chamber reamer, bought a Green Mountain 22 Magnum barrel, (what's thats? That's a barrel dedicated to the 22 Magnum, has the correct bore and groove, but 14 twist) put it on an AR15 as a bull barrel and indeed it does shoot very well. It's past time the manufacturers start building more accurate 22 Magnums.

Now back to the AR15 using 22 conversion kits. I'm out to prove that the 7 twist can be just about as accurate as the 12 twist when all the conditions that cause it to be less accurate in a 7 twist are recognized and fixed. So far I think I'm heading in the right direction. This is not to turn the AR15 with the 22 convesion kit into a match rifle as I already have that in other 22 firearms. One more thing on my HBAR I don't have a free floating barrel and forearm tube like yours does. Mine is a stock pre ban HBAR so the resting the forearm/barrel on the front rest can and does influence how it shoots. So we shall see what I get in the end. I have many irons in the fire and this may take a while.

This week I will see how I can get the conversion device to fit the chamber better. I'm going to check to see if the datum line on the device chamber does indeed butt up against the datum of the rifle's chamber. I realize the military wasn't out to turn a M16 into a match target rifle and was only a cheaper means to train soldiers. Maybe we shall find out what it is really capable of.

I appreciate your help on this so far and hope it continues.

TD

[Larry Gibson]

TD1886

"I'm out to prove that the 7 twist can be just about as accurate as the 12 twist when all the conditions that cause it to be less accurate in a 7 twist are recognized and fixed."

Good luck with that.

"One more thing on my HBAR I don't have a free floating barrel and forearm tube like yours does."

No, my 12" twist milspec barreled AR does not have a free floating barrel, it is milspec with M16A2 handguards. My Colt HBar with a 9" twist heavy barrel is free floated with a tube fore end.

[TD1886]

TD1886

"I'm out to prove that the 7 twist can be just about as accurate as the 12 twist when all the conditions that cause it to be less accurate in a 7 twist are recognized and fixed."

Good luck with that.

"One more thing on my HBAR I don't have a free floating barrel and forearm tube like yours does."

No, my 12" twist milspec barreled AR does not have a free floating barrel, it is milspec with M16A2 handguards. My Colt HBar with a 9" twist heavy barrel is free floated with a tube fore end.

That clears up the rifles you have, thanks.

Okay today I took the unit out of the rifle and cleaned it. Then I marker pen the entire cartridge chamber on the end of it in addition to the round base of it that fits into the barrel extension at the lugs area. It confirmed my fears. There was one part of it that contacted the chamber. I was especially interested in the datum line on the unit cartridge and there were zero marks on it. I'm right, at least with the Colt unit, that it's basically loose in the chamber of the rifle. No wobbly loose, but loose in the sense not touching. I have the diameter of the unit cartridge portion in comparison with a fired 5.56 and the two area's I measure the unit cartridge was .002 and .0028 difference. That's a lot of slop so that bullet has a huge chance of entering the bore crooked and the 7 twist has a huge chance of killing it's accuracy with the high rpm.

I think the accuracy with my unit and rifle will suprise you. So far it's very usuable at 50 yards.