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Posted: 1/22/2006 11:20:57 AM EDT
I am suffering from an uninformed purchase at a recent gunshow. I am looking for a decent gunsmith in the Milwaukee area that has experience with AR-15's. Any info greatly appreciated.

Glenn
Cudahy, WI
Link Posted: 1/22/2006 11:24:31 AM EDT
What kind of work do you need done?
Link Posted: 1/22/2006 3:22:54 PM EDT
Mike Bykowski, owner of High Performance International. He's done all the work to my Service Rifle, and I know he works on varminters too. I've always been pleased with his service and quality.
Link Posted: 1/22/2006 4:05:16 PM EDT
+1 for Mike Bykowski, but what do you need done? There's plenty of arfcommers around Milwaukee who probably have tools and could help you out.
Link Posted: 1/22/2006 6:53:26 PM EDT
What did you buy, for how much money, and what's wrong with it?

The clique around here beats the living heck out of weapons, so we're pretty good at replacing the parts we break.
All of our rifles run like a top on the cheapest ammo available, so we must be doing something right.

Did you try throwing it on the floor and calling it dirty filthy names?
Link Posted: 1/22/2006 6:53:57 PM EDT
[Last Edit: 1/22/2006 7:03:27 PM EDT by Throttle-Junkie]
.
Link Posted: 1/22/2006 6:55:26 PM EDT
[Last Edit: 1/22/2006 7:03:11 PM EDT by Throttle-Junkie]
Wow!

Triple taps are rare.
Link Posted: 1/22/2006 8:20:05 PM EDT

Originally Posted By Throttle-Junkie:
What did you buy, for how much money, and what's wrong with it?

The clique around here beats the living heck out of weapons, so we're pretty good at replacing the parts we break.
All of our rifles run like a top on the cheapest ammo available, so we must be doing something right.

Did you try throwing it on the floor and calling it dirty filthy names?



I was at the Central WI. show last week, and bought a used Bushmaster XM15-E2S. It has a Colt 20" 1/9 HBAR on it. I bought it on a whim, and didn't give it a close enough look. Got home from the show, took it to the range and found it shoots way left with A2 sights at zero windage. What I see is that the FSB is canted right. I just don't know if the FSB is pinned on crappy, or if the barrel is mis-timed. I hope it's the latter, as I see where the barrel is galled from a barrel vice, making me think it wasn't installed properly, and maybe can be retightened to get it at TDC. The other bugaboo is a gouge in one of the lands right at the crown. I really don't know if this is affecting my shooting yet, as I have only had two outings with this thing. I was out today and did the proper sight in at 25yds, but ended up with some some pretty lousy groups at 100yds. I guess I would like to get an idea of how much it would cost to get the barrel recrowned if necessary, and get the barrel timed right. I think I would be ashamed to take it to Mike Bykowski after reading about what he builds. I haven't been to any gunsmith in the area yet, as I haven't been at this too long.
Throttle-junkie, it's still too new to me to throw it on the floor yet. That comes after I stick some more cash in it and it still shoots crappy.

Glenn
Cudahy, WI
Link Posted: 1/23/2006 4:26:22 AM EDT
[Last Edit: 1/23/2006 4:56:12 AM EDT by Throttle-Junkie]
The barrel cannot be mis-timed by much. There's a slot and tab configuration. It has a small amount of play. Sometimes the tab makes contact with the end of the slot before everything is lined up. In this case, most folks file the slot a fuzz wider so that the barrel assembly can be timed correctly.

If the rear sight needs to be bottomed out to one side or the other, and still won't zero, a common problem is for the barrel nut to have been over-tightened; which among other things, can bend the index pin.

A barrel that shows gouging from a barrel vice has almost certainly been installed by a toothless bubba who decided to brave the task without an action block. The upper receiver and the barrel assembly just slide together. It's a little bit like the drain-trap under a sink in so much as the nut slides over the pipe to snug the connection together. The nut is snugged to 75 ft-lbs. At this point the star looking part that the handguards grab onto must be in the correct position to permit the gas-tube to enter the receiver. This is where the factory sometimes screws up the process. The simply tighten the nut beyond 75 lbs, until the next space is even with the gas-tube entrance. The correct process would be to stop, remove the nut and barrel, and slightly relieve the receiver so that the hole lining up, and the barrel-nut torque reaching 75 lbs occur at the same time.

Either the receiver, or the barrel must be held stationary while the nut is tightened. The action block is a specialized chunk of plastic that clamps around the reciever and fits in a vice.
If the Bubba-Smith that changed your barrel didn't have an action block, then I'm betting he didn't have a torque wrench either. Who knows what that nut is tightened to. Sounds like he erred on the side of REALLY tight.

Hard to separate your crown issues from the assembly issues at this point. I've seen over-tightened barrels that had perfect crowns, but wouldn't group. There are plenty of folks that have shortened their own barrels, squared up the end, and recrowned at the kitchen table without a lathe.
The process generally involves taking an truly round metal object, like a ball bearing, lubing with grinding compound, and using the ball to polish the imperfection out of the crown.

If anything here doesn't make sense, ask, and I'll try to articulate it more clearly.

You have to be honest about your mechanical abilities when deciding whether or not to work on it yourself. You weren't intimidated by trroubleshooting the rifle, and you know what a crown is supposed to look like, so your obviously not an un-mechanical gun-dope.

Worst case, Bubba fucked up the upper receiver, chewed up the threads, and warped the front plane. The index pin should be straightenable. The crown is truable.

If the barrel needs to be yanked, crowned, pin straightened, and reinstalled ...... I'm guessing about $150.
If you need a new upper, add ~$200.
In this price range, you can shop for a new barreled upper that you just slap on and go, while selling your upper (with disclosure) ro recoup a few bucks.

Might be worth your while to make it out to a shoot and let the WI arfcom crew give you a second opinion on the rifle's condition. Ever go to RCLRC?
Link Posted: 1/23/2006 5:46:06 AM EDT
[Last Edit: 1/23/2006 5:47:52 AM EDT by photoman]

Originally Posted By BuzzWindrip:

Originally Posted By Throttle-Junkie:
What did you buy, for how much money, and what's wrong with it?

The clique around here beats the living heck out of weapons, so we're pretty good at replacing the parts we break.
All of our rifles run like a top on the cheapest ammo available, so we must be doing something right.

Did you try throwing it on the floor and calling it dirty filthy names?



I was at the Central WI. show last week, and bought a used Bushmaster XM15-E2S. It has a Colt 20" 1/9 HBAR on it. I bought it on a whim, and didn't give it a close enough look. Got home from the show, took it to the range and found it shoots way left with A2 sights at zero windage. What I see is that the FSB is canted right. I just don't know if the FSB is pinned on crappy, or if the barrel is mis-timed. I hope it's the latter, as I see where the barrel is galled from a barrel vice, making me think it wasn't installed properly, and maybe can be retightened to get it at TDC. The other bugaboo is a gouge in one of the lands right at the crown. I really don't know if this is affecting my shooting yet, as I have only had two outings with this thing. I was out today and did the proper sight in at 25yds, but ended up with some some pretty lousy groups at 100yds. I guess I would like to get an idea of how much it would cost to get the barrel recrowned if necessary, and get the barrel timed right. I think I would be ashamed to take it to Mike Bykowski after reading about what he builds. I haven't been to any gunsmith in the area yet, as I haven't been at this too long.
Throttle-junkie, it's still too new to me to throw it on the floor yet. That comes after I stick some more cash in it and it still shoots crappy.

Glenn
Cudahy, WI



Well there could be a couple of issues, If the FSB is canted that is an easy fit. Trust me I know this I'm notorious for canted FSBs(slightly not to much cant but enough.) I had to take the FSB off my SBR and re do it because of that. The barrel should be indexed properly because well it's difficult not to get it indexed correctly, but there still could be issues there. I'd have to dig around in the troubleshooting forum to find the post on it.

The damage to the crown sticks out as a potential issue as well as any damage like that can cause issues. It could be as simple as having it recrowned. There are plenty of places to have that done. ADCO can do it for you as well a Krieger barrels. Let us know when you got free time and I'm sure one of us can meet up with you and help you trouble shoot it.

As T_J said a lot of us are pretty good at breaking guns through hard use so fixing them isn't an issue.


ETA: T_J you sure about this

The nut is snugged to 75 ft-lbs.
I was always told/have read 80 ft-lbs.
Link Posted: 1/23/2006 9:13:13 AM EDT
You've just undermined my confidence.
I was typing from memory.
Could be off by a couple foot-pounds I suppose.
Link Posted: 1/23/2006 1:03:01 PM EDT
Throttle-Junkie, photoman, thanks for the replies. I am a member at RCLRC, and was there shooting this Bushmaster last night. The canted FSB was throwing me off as I had the urge to twist the gun to straighten it up. I did the battlesight zero at 25yds, and had very nice tight groups. 100yds was a different story. All over the paper. I really don't know what to expect from a gun like this. I just hope I can get it to group better than my Savage/Enfield No.4.

I am not opposed to trying to tweak the barrel myself, especially if it saves $150 bucks or more. It would be a crying shame if the bubba that barreled this thing trashed the upper receiver as it looks like it is brand new. I know there is a guy that shows up at the Bob and Rocco shows that has a lot of AR parts; would I find a barrel wrench and action block there? Throttle-Junkie,as far as cutting and recrowning at home goes, if that is something that can be initiated with a hack-saw, I can do it. My question is how to get the cut straight enough so that I don't join the ranks of the bubba 'smiths. I have heard of the ball bearing/valve grinding compound trick to work up a new crown. I will definitely wait to get the barrel indexed before I try any cutting. I need more trigger time with this gun (and in general) before I can say it is the nicked crown.

Glenn
Cudahy, WI
Link Posted: 1/24/2006 4:55:04 AM EDT
[Last Edit: 1/24/2006 4:58:23 AM EDT by FMD]

Originally Posted By BuzzWindrip:
I am a member at RCLRC,



You're golden, then. Many of us are as well. If you need us "in person" give a shout out here in the HTF.


I did the battlesight zero at 25yds, and had very nice tight groups. 100yds was a different story. All over the paper.


Not enough info. What ammo were you using? This can make a HUGE difference.


...would I find a barrel wrench and action block there(at the gunshow)?


IM photoman, and he can let you borrow my wrench and block (he should be done with it by now). No need to buy the tools we already have.


My question is how to get the cut straight enough so that I don't join the ranks of the bubba 'smiths. I have heard of the ball bearing/valve grinding compound trick to work up a new crown. I will definitely wait to get the barrel indexed before I try any cutting. I need more trigger time with this gun (and in general) before I can say it is the nicked crown.


Don't cut the barrel, just lap the end.

45* Muzzle lapper from Brownells
Silicon Carbide lapping compound (180 grit should do it, depending on how bad it is)

That way, I can borrow the tools after you're done with the job. Seriously though; if it's just a nick, lapping will probably take care of it.
Link Posted: 1/24/2006 7:40:59 AM EDT

Originally Posted By FMD:

Originally Posted By BuzzWindrip:
I am a member at RCLRC,



You're golden, then. Many of us are as well. If you need us "in person" give a shout out here in the HTF.


I did the battlesight zero at 25yds, and had very nice tight groups. 100yds was a different story. All over the paper.


Not enough info. What ammo were you using? This can make a HUGE difference.


...would I find a barrel wrench and action block there(at the gunshow)?


IM photoman, and he can let you borrow my wrench and block (he should be done with it by now). No need to buy the tools we already have.


My question is how to get the cut straight enough so that I don't join the ranks of the bubba 'smiths. I have heard of the ball bearing/valve grinding compound trick to work up a new crown. I will definitely wait to get the barrel indexed before I try any cutting. I need more trigger time with this gun (and in general) before I can say it is the nicked crown.


Don't cut the barrel, just lap the end.

45* Muzzle lapper from Brownells
Silicon Carbide lapping compound (180 grit should do it, depending on how bad it is)

That way, I can borrow the tools after you're done with the job. Seriously though; if it's just a nick, lapping will probably take care of it.




Yup I'm done with them till I find a 16in 1/7 hbar.


BuzzWindrip I'll be out at the club friday sometime to do some shooting and move some stuff around and put some stuff out for the NFA shoot. If ya want come on out and bring the gun and I'll take a look at it.

Link Posted: 1/24/2006 2:09:04 PM EDT
FMD, I had a few boxes of stuff I picked up at the last show, Winchester white box, some S&B, and 2 boxes of what I assume was older Wolf HP's as they were laquer coated. By the time I started shooting at my 100yd. target, there were only had 5 rounds of Winchester left. It appeared to group ok, but when I started with the Wolf, it all went to hell.

As far as the crown goes, I use the term to loosely I guess; what it actually looks like is the the last 1/16" of one of the lands is gouged, the actual crown is intact. I don't think that crowning tool would go deep enough to clean that up. I'll hold off on any fixes to that until I get some decent quantities of good ammo downrange. I haven't been shooting all that long, and this gun has the worst trigger of any gun I own, so that is probably a factor as well. Thanks for the offer on the tools, I'll try to hook up with photoman on that.

photoman, I work first shift so the earliest I ever get to the range on a weeknight is about 4pm. Will you still be there then? I would appreciate a second opinion. Thanks for the help guys.

Glenn,
Cudahy, WI
Link Posted: 1/24/2006 2:32:50 PM EDT
Guys,

You all offer sound advice, but what I really think Buzz is suffering is a case of the "Frankenupper."
The barrel nut is fine, they are really hard to mess up, unless the index pin is broken off.

I'll bet that the upper was made from a naked Colt barrel, that somebody got at a gun show without the FSB. Then the owner tried to marry up any old FSB with the underbarrel grooves. Have you ever tried it with a Colt? Those bastards always have to have measurements that are off from mil-spec, so you usually can't put Bushmasters on Colts and vice versa. You are forced to buy Colt products. The owner got a FSB that was close enough and drilled the other hole to fit as best he could and pounded in the taper pins only to find the sight a couple of degrees off. Very common. I've done it, my other armorers have done it as well.

Not to fret, Buzz. Unscrew the flash hider (if it has one) (Colts are on tight). Then just pound out the gas tube pin, the taper pins (as you are looking down the barrel from the receiver, they pound out from left to right, although on your upper, who knows), and remove the FSB. If you know someone with a lot of Colt marked FSBs, you might get lucky and find one that matches the undergrooves better, but I'd advise you to just buy one of those pin-on FSBs from Armalite, Model one, etc for $40. You can index that baby right on. Use green Locktight and you shouldn't have it moving on you. Use the red stuff for permanent application if you want. Somebody should have an index rod to help you center it on, or just do the best you can via the eyeball method. Then tighten the screws.

If there is too much play with your handguards fitting well into the front ring, you can try using a spacer to fill in the gap or you'll have to bite the bullet and free-float the barrel, which is another $130.

A lot of Marines on our shooting team use these pin-on FSBs on their Armalite uppers. If it's good enough for them, it should be good enough for you.

The gouge in the crown should be fixed as described. Yes, that can throw you off, especially if you are shooting the 1:7 twist barrel and heavy (62gr) loads. You aren't shooting that Wolf stuff are you? NOBODY in NASCAR runs on Fleet Farm tires, so use the better stuff. Not necessarily the Black Hills stuff, but at least Winchester USA (available at Wal-Mart) or Federal.

Kip Johnson
Quantico Marine Base
Quantico, VA


Link Posted: 1/24/2006 3:46:34 PM EDT
[Last Edit: 1/24/2006 3:50:16 PM EDT by FMD]

Originally Posted By BuzzWindrip:
FMD, I had a few boxes of stuff I picked up at the last show, Winchester white box, some S&B, and 2 boxes of what I assume was older Wolf HP's as they were laquer coated. By the time I started shooting at my 100yd. target, there were only had 5 rounds of Winchester left. It appeared to group ok, but when I started with the Wolf, it all went to hell.



Zero with quality ammo, not Wolf. Don't get me wrong, I love Wolf for class and to plink, but if you're looking for groups, BH blue box is the way to go.


As far as the crown goes, I use the term to loosely I guess; what it actually looks like is the the last 1/16" of one of the lands is gouged, the actual crown is intact.


Raised metal on an edge? You could always "fire lap" that out. Probably wouldn't have that big of an affect on accuracy if it doesn't extend to the crown.


This gun has the worst trigger of any gun I own, so that is probably a factor as well.


Welcome to the AR platform.

If you don't have an aversion to the WECSOG thing, a dremel with a felt end and polishing compound can do wonders (note do NOT use anything else on the end of the dremel!!!).


Thanks for the offer on the tools, I'll try to hook up with photoman on that.

photoman, I work first shift so the earliest I ever get to the range on a weeknight is about 4pm. Will you still be there then? I would appreciate a second opinion.



I think he normally gets off at three, but his schedule changed recently, IIRC. You can also give me a yell, and I can see what I might be able to do.


Thanks for the help guys.


Group hug!


Originally Posted By bailey89:
You all offer sound advice, but what I really think Buzz is suffering is a case of the "Frankenupper."





Wait a minute... you just described all the uppers I have.

Guess I have the disease as well.


...I'd advise you to just buy one of those pin-on FSBs from Armalite, Model one, etc for $40. You can index that baby right on.


He could go with a clamp-on from BM/YHM as well, if that's the issue.
Link Posted: 1/24/2006 6:50:47 PM EDT
Don't even CONSIDER fucking with the front sight post until the rifle starts grouping.
If it wont shoot a group then moving the sights around is just an exerdcise in frustrating yourself.

A barrel nut IS EASY to screw up.
Bushmaster is notorious for fucking it up at the factory. Ask an armorer.
If you over tighten it excessively (Bubba-style making sure it's on there good), and the threads start to give, they will give unevenly, the pressure holding the barrel to the upper will be far from uniform, and funky barrel vibrations will send rounds all over the fucking place.

The barrel nut screws on to the receiver. The receiver must remain stationary for this to happen. There are vice gouges on your barrel. The barrel was held stationary, and the index pin is what kept the receiver from rotating while the barrel-nut was tightened. The pin is most likely bent.
Even if it is not bent, there is 75+ ft-lbs of torque forcing the pin against the edge of the gap that it fits into. Bad news for grouping on a bench.

If it were me, I'd spin the nut off, pull the barrel and have a good look at everything.
You'll know a lot more then. The pin may or may not be bent. The gap may be chipped. You can inspect the threads. You can verify that the index pin and the front sight post are inline.
Link Posted: 1/24/2006 6:59:49 PM EDT

Originally Posted By FMD:
Welcome to the AR platform.

If you don't have an aversion to the WECSOG thing, a dremel ...



(OMG .... YOU DIDN'T just recommend a dremel to someone trying to get their rifle shooting straight)

Learn to shoot the base rifle.
(Where have I heard that before?)

National match triggers and custom this-and-thats remind me of the guys that go bowling with thirteen plastic and velcro prostetic devices attached to themselves.

Link Posted: 1/24/2006 8:42:43 PM EDT
[Last Edit: 1/25/2006 3:39:52 AM EDT by BuzzWindrip]
Ok, before I do anything, I am going to try to hook up with photoman for that second opinion. Sounds like I should get the barrel nut off to get a look at that index pin, so hopefully I can get the tools to do the job. I am not averse to buying some tools if needed. Then I will buy some decent ammo (and dies, etc so I can reload this stuff) and get to the range, rezero with the good stuff, and shoot enough targets to see if it does actually group. I am assuming I don't have to take off the FSB to get the barrel wrench on (have to look in the build it yourself section a bit more) when it comes to that. How much jaw opening is required on a vice to get the action block in there?. I will hold off on any other cures till all else fails. Baily89, I think you may be right about the Frankenupper; both upper and lower look new, BC didn't even have any shine to the contact surfaces, same with the charging handle, not a bit of wear. Guess the Colt barrel is something that was laying around. There is no threading or muzzle device, so this must be a pre AWB sunset barrel.

Glenn
Cudahy, WI
Link Posted: 1/25/2006 4:03:22 AM EDT
[Last Edit: 1/25/2006 4:03:52 AM EDT by TheKill]
Find a machine competent machine shop and have them cut that barrel down on a lathe, or send it to ADCO.

Believe it or not, a cone bit on a dremel WILL work if you are talking about a nick on the very crown, and it's done veeeeeery carefully. Better to do it on a bolt rifle, since a factory bolt rifle barrel is a $5 part. If it doesn't work, rebarrel with a good one. LOL.......

TJ.....I have been using 75 ft. lbs. Works for me.....

FMD, Black Hills Blue Box 68 grain match hasn't shot for shit in any rifle I have tried it in, including a DPMS 1/8 20" stainless match, a regular old service rifle, and a 24" Winchester HB Stealth. Some of the guys at Snipercountry report similiar experiences. Now, the 77 grain Mk262 is a different story........but that probably won't shoot very well out of a 1-9 twist.

Guys, I have the necessary tools to work on that rifle as well, let me know if you need a hand.
Link Posted: 1/25/2006 4:26:11 AM EDT

Originally Posted By Throttle-Junkie:

Originally Posted By FMD:
Welcome to the AR platform.

If you don't have an aversion to the WECSOG thing, a dremel ...



(OMG .... YOU DIDN'T just recommend a dremel to someone trying to get their rifle shooting straight)





No, I reccomended a dremel, a felt-tip, and polishing compound to smooth out his trigger a bit. All you had to do was to read my quote of Buzz's previous statement, and the few words (and rather distinctive warning) after "dremel" to understand. Talk about selective reading taken wholly out of context. Wow!


Originally Posted By TheKill:
FMD, Black Hills Blue Box 68 grain match hasn't shot for shit in any rifle I have tried it in, including a DPMS 1/8 20" stainless match, a regular old service rifle, and a 24" Winchester HB Stealth. Some of the guys at Snipercountry report similiar experiences. Now, the 77 grain Mk262 is a different story........but that probably won't shoot very well out of a 1-9 twist.



Dangit, it's an epidemic! I didn't reccomend 68 Gr. for zeroing. BH makes a variety of other bullet weights that come in a blue box. Also, FWIW, I've seen reports of 68 Gr. not grouping for crap at 100 that were sub-moa past 200 (Fedgunner from MN, IIRC). His theory was that the bullet wasn't quite yet stable at 100, and since he's a ballistician working at a major ammo manufacturer, I'll take his word for it (even though I can't get it to group for shit either).

I'm busting on you guys cause I know you can take it. Let's get Buzz here set up and GTG, then we can add him to the sewing circle, too. mmmkay?
Link Posted: 1/25/2006 4:32:27 AM EDT
[Last Edit: 1/25/2006 5:09:31 AM EDT by photoman]
BuzzWindrip after 4 is not a problem, I have the day off so whatever works for you is fine with me.


ETA: on the 68gr black hills. That stuff used to shoot beautifuly out of my guns, but a lot of people were having issues with it. They changed a bit of the formula for it and it started working better in more guns, but now my guns don't like it It happened to a lot of people. I pretty much made the decision that I'll shoot 55gr(class,blasting etc..) or 75 gr(for serious shit). I still pick up a box here and ther eof the 68gr stuff just to try it and see if I get lucky and get something that works.
Link Posted: 1/25/2006 10:58:38 AM EDT

Originally Posted By FMD:
Also, FWIW, I've seen reports of 68 Gr. not grouping for crap at 100 that were sub-moa past 200






(Fedgunner from MN, IIRC). His theory was that the bullet wasn't quite yet stable at 100, and since he's a ballistician ...




'Ballistician' ??



I'm having trouble picturing a bullet trajectory that is all spread out at 100, but then comes back to a focal point at 200.
Do they use a nail file to raise the stitching on the slugs and then coat the brass with pine-tar to get a better grip?







But wait a minute ....












Now that you mention it .....
















I do remember seeing something like that once before ......



















His rounds had a flight path similar to the one you're describing.






Which ammo did you say that was?

Link Posted: 1/25/2006 3:27:55 PM EDT
[Last Edit: 1/25/2006 3:48:00 PM EDT by FMD]

Originally Posted By Throttle-Junkie:



I knew that if I threw enough sand in your mangina, you'd post a photo of yourself.



"ballistician" = Somebody that studies ballistics for a living, smartypants.

Looked for the thread, but can't find it in the Archives (was when we were all looking at doing a DE Precicion rifle class). I know it sounds crazy, but I thought for sure that's how Fedgunner put it.

ETA: We probably should knock off with the hijacks of Buzz's thread now.

Edit 2: An excerpt from a ballistician's article on the 69 Gr. SMK bullet and it's instability at close range:

"Bullet coning motions usually tend to damp out as the bullet travels down-range. That is, the coning motion of a bullet is largest when it leaves the muzzle and grows smaller as the bullet flies downrange, basically because of air friction. Some shooters refer to this effect as the bullet “going to sleep..."

Link to the article on Exterior Ballistics
Link Posted: 1/25/2006 7:37:17 PM EDT

Originally Posted By FMD:

Originally Posted By Throttle-Junkie:
www.2nilssons.com/Nilsson%20and%20Dawson%20Family/kln%20-%20baby,%20tutu.jpg


I knew that if I threw enough sand in your mangina, you'd post a photo of yourself. hock.gif

hat
Looked for the thread, but can't find it in the Archives (was when we were all looking at doing a DE Precicion rifle class). I know it sounds crazy, but I thought for sure that's how Fedgunner put it.

ETA: We probably should knock off with the hijacks of Buzz's thread now. he
"Bullet coning motions usually tend to damp out as the bullet travels down-range. That is, the coning motion of a bullet is largest when it leaves the muzzle and grows smaller as the bullet flies downrange, basically because of air friction. Some shooters refer to this effect as the bullet “going to sleep..."

Link to the article on Exterior Ballistics



photoman, catch you on Friday then...

As far as the hijack, carry on. I enjoyed the turn to ballistics. Tomorrow evening is my 6th grade son's science fair at the local public school. His project: ballistics. For exterior ballistics we charted actual bullet drop over 100 yards with subsonic .22 LR, shot at intervals on the same target, and labeled each bullet hole and measured the rise or drop from point of aim, then plotted a trajectory curve on paper. For terminal ballistics we shot 7 pine boards with standard velocity .22 LR and .223 for comparison. The fact the .223 tumbled in the last 3 boards and exited sideways intact, leaving a perfect exit keyhole is golden. I have it set up so the boards are separated and numbered to see the progession in and through the boards. The best part is that his science teacher was 100%behind this (no cartridges in school though) and so was the principal, who definitely veers to the left of center in philosophy. Now I hijacked my own thread...

Glenn
Cudahy, WI
Link Posted: 1/25/2006 8:07:15 PM EDT
Nice going, Buzz.

You'r son knows more about guns and ballistics than 90+% of the guys that deer-sight their rifles at RCLRC.



Seriously, IT IS a great headstart, and not just for shooting.
Later on, concepts in Newtonian Mechanics will be easy to understand because he will be familiar with a practical example of projectile motion.

Way to get involved.
Link Posted: 1/26/2006 4:05:02 AM EDT
[Last Edit: 1/26/2006 4:06:08 AM EDT by FMD]

Originally Posted By Throttle-Junkie:
Nice going, Buzz.

Your son knows more about guns and ballistics than 90+% of the guys that deer-sight their rifles at RCLRC.



+1

Now on to his 7th Grade Science project: Bullet Ballistic Coefficients and Bullet Coning

"The coning motion caused by the initial yaw of a bullet when it exits the muzzle generally damps out as the bullet flies — that is, it decreases in amplitude as the bullet travels downrange. This is because the causes of initial yaw are transient in nature. In other words, these causes occur only at the muzzle and do not persist as the bullet flies. Also, the aerodynamic forces caused by the coning motion are restoring forces (tend to improve stability of the bullet) as long as the amplitude of the coning motions is not large enough to cause loss of stability (tumbling). This is the fundamental cause of many anecdotes heard by these authors that 'my rifle shoots 1.5 MOA groups at 100 yards, 0.8 MOA groups at 200 yards, and 0.6 MOA groups at 300 yards.'..."

From the same author of the previous link.

No references to the 5th Element needed, right TJ?
Link Posted: 1/26/2006 5:22:29 AM EDT
[Last Edit: 1/26/2006 5:23:39 AM EDT by Throttle-Junkie]
Uh huh ........

Commonly refered to as 'tail wag' because of the oblong holes that are left in the paper.
This person refers to it as coning motion implying that the forward most portion of the projectile remains centered while the rear sweeps out an orthagonal circular path.
In actuallity, there will be an axial point just forward of the projectile's center of mass.
Meaning that there are two cones being swept, one opening forward, and a larger one opening rearward.

This effect will cause the diameter of the holes made by the profectile to become smaller as the tangent motion damps out.

The holes themselves get smaller, but their centers don't move closer together.

Lets say I put a target at 100, and another one directly behind it at 200.
You get on the bench and shoot your normal basketball sized group at 100.
Do you think that diminshing tail wag will cause the rounds to bunch back down to a baseball at 200?

I don't think so.
I think thier divergent paths continue to spread them further apart; like a shotgun blast.

We could always defer to Senator Arlen Specter's expertise.



He's the one who authored the magic bullet theory, whereby Kennedy was hit three times from different directions by one bullet.

Those damned Carcanos must be some tail-waggin sons-a-guns, eh?



Link Posted: 1/26/2006 1:36:08 PM EDT
Awwright now!

Which one of you is confused as to the difference between a kilt and a tutu?

As to my experience. It was described accuratly. The instructor was the one that informed me of this particular phenomenon. He stated that the bullet had not "gone to sleep" at 100 yards.
About a week or two later I was watching a program on sniper training that showed this perfectly out of a .308 bolt gun. As the video was shot from directly behind, you recieved no sense of how far down range the bullet sabilized. In archery they have something similar called the "Archer's paradox" A different cause, but much the same result..

I'm going to repeat this test in warmer weather. I didn't want to waste the rest of the classes time diagnosing the quirks in my rifle.
Link Posted: 1/26/2006 2:58:06 PM EDT
[Last Edit: 1/26/2006 3:24:32 PM EDT by FMD]
Edit: Thought better of it.
Link Posted: 1/27/2006 1:14:47 PM EDT

Originally Posted By BuzzWindrip:

Originally Posted By FMD:

Originally Posted By Throttle-Junkie:
www.2nilssons.com/Nilsson%20and%20Dawson%20Family/kln%20-%20baby,%20tutu.jpg


I knew that if I threw enough sand in your mangina, you'd post a photo of yourself.



"ballistician" = Somebody that studies ballistics for a living, smartypants.

Looked for the thread, but can't find it in the Archives (was when we were all looking at doing a DE Precicion rifle class). I know it sounds crazy, but I thought for sure that's how Fedgunner put it.

ETA: We probably should knock off with the hijacks of Buzz's thread now.

Edit 2: An excerpt from a ballistician's article on the 69 Gr. SMK bullet and it's instability at close range:

"Bullet coning motions usually tend to damp out as the bullet travels down-range. That is, the coning motion of a bullet is largest when it leaves the muzzle and grows smaller as the bullet flies downrange, basically because of air friction. Some shooters refer to this effect as the bullet “going to sleep..."

Link to the article on Exterior Ballistics



photoman, catch you on Friday then...

As far as the hijack, carry on. I enjoyed the turn to ballistics. Tomorrow evening is my 6th grade son's science fair at the local public school. His project: ballistics. For exterior ballistics we charted actual bullet drop over 100 yards with subsonic .22 LR, shot at intervals on the same target, and labeled each bullet hole and measured the rise or drop from point of aim, then plotted a trajectory curve on paper. For terminal ballistics we shot 7 pine boards with standard velocity .22 LR and .223 for comparison. The fact the .223 tumbled in the last 3 boards and exited sideways intact, leaving a perfect exit keyhole is golden. I have it set up so the boards are separated and numbered to see the progession in and through the boards. The best part is that his science teacher was 100%behind this (no cartridges in school though) and so was the principal, who definitely veers to the left of center in philosophy. Now I hijacked my own thread...

Glenn
Cudahy, WI



I just got nback into town and I'm running a little late I'll be out there closer to 5. But I'll be out there Gotta drop off some stuff for the shoot toarrow.
Link Posted: 1/27/2006 5:31:40 PM EDT
[Last Edit: 1/27/2006 5:32:46 PM EDT by JJREA]
Buzz, your rifles a piece of crap. Might as well give it to me.

Just teasing.

If you can get that thing to group good, using the large Aperture at 100 yards, you're a much better shot than me. Like I said before, try it with the small ap. I can't remember if you told me that you did try it with the small ap. Because I thought I remember saying you shot it with the large ap. Either way, what FMD said is good.

Don't try the 68's though. They are very very barrel finicky. I've always had good luck with the 52's for accuracy. Or just try the 55 FMJ. Well heck, try the 68's too. Try as many as you can get your hands on because they (barrels) have a tenancy to be prejudiced. At least mine have.
Link Posted: 1/27/2006 8:43:08 PM EDT

Originally Posted By JJREA:
Buzz, your rifles a piece of crap. Might as well give it to me. hat
Don't try the 68's though. They are very very barrel finicky. I've always had good luck with the 52's for accuracy. Or just try the 55 FMJ. Well heck, try the 68's too. Try as many as you can get your hands on because they (barrels) have a tenancy to be prejudiced. At least mine have.



Piece of crap barrel is what I was thinking 10 rounds into my first target today. All over the place. Small aperture. Remington green and white box ammo I picked up from Wally World for $3.97 a box. 55gr FMJ. Switched to large aperture, same thing next 10 rounds. Starting to wonder if my skill level is the biggest factor as nothing can shoot this sloppy. But I can shoot nice tight groups all day with almost any of my old C&R milsurps, so I ain't that bad. Second box of ammo, back to the small aperture, but this time I crank the rear sight down past 8/3 to where it bottoms out, so there is no movement of the sight at all. Five shots, I look through the scope and voila, a group that looks just over an inch. I fired 40 shots into two groups of roughly 2 1/2" each with 4 flyers. So what happened? First box of ammo was crap? Sight being cranked down eliminating any possibility of movement? Hopefully I will be able to duplicate at least what I was able to shoot today. I have a tidy pile of brass now, but no tumbler. Going to buy some dies and bullets from GM tomorrow, I will get both 55 and 68gr and try them. One thing I do notice about the fired brass from this gun; it really looks gungy. My FAL doesn't muck up new brass up that bad. The nice shiney new .223 brass looks like it has been sitting outside for a couple of weeks after coming out of my AR's chamber. I did pick up a chamber brush tonite at the gunshow, so maybe that will help.

Link Posted: 1/28/2006 6:42:04 PM EDT

Originally Posted By BuzzWindrip:

Originally Posted By JJREA:
Buzz, your rifles a piece of crap. Might as well give it to me.

Just teasing.

If you can get that thing to group good, using the large Aperture at 100 yards, you're a much better shot than me. Like I said before, try it with the small ap. I can't remember if you told me that you did try it with the small ap. Because I thought I remember saying you shot it with the large ap. Either way, what FMD said is good.

Don't try the 68's though. They are very very barrel finicky. I've always had good luck with the 52's for accuracy. Or just try the 55 FMJ. Well heck, try the 68's too. Try as many as you can get your hands on because they (barrels) have a tenancy to be prejudiced. At least mine have.



Piece of crap barrel is what I was thinking 10 rounds into my first target today. All over the place. Small aperture. Remington green and white box ammo I picked up from Wally World for $3.97 a box. 55gr FMJ. Switched to large aperture, same thing next 10 rounds. Starting to wonder if my skill level is the biggest factor as nothing can shoot this sloppy. But I can shoot nice tight groups all day with almost any of my old C&R milsurps, so I ain't that bad. Second box of ammo, back to the small aperture, but this time I crank the rear sight down past 8/3 to where it bottoms out, so there is no movement of the sight at all. Five shots, I look through the scope and voila, a group that looks just over an inch. I fired 40 shots into two groups of roughly 2 1/2" each with 4 flyers. So what happened? First box of ammo was crap? Sight being cranked down eliminating any possibility of movement? Hopefully I will be able to duplicate at least what I was able to shoot today. I have a tidy pile of brass now, but no tumbler. Going to buy some dies and bullets from GM tomorrow, I will get both 55 and 68gr and try them. One thing I do notice about the fired brass from this gun; it really looks gungy. My FAL doesn't muck up new brass up that bad. The nice shiney new .223 brass looks like it has been sitting outside for a couple of weeks after coming out of my AR's chamber. I did pick up a chamber brush tonite at the gunshow, so maybe that will help.




I've never found UMC in 55 grain to group for crap either. Brass is nice and goes bang but it's not very accurate in the 3 AR's I've tried it in. Actually, I take that back. I haven't tried it in my newest one so, the 2 others that I've had. Yeah, you gotta try some black hills.

If you're shooting MOA with it, especially with irons, it doesn't need to be any more accurate than that. Unless you want the world or something.
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