2Xalpha

Thousand millimeters or inches?

Check out this "Accuracy International magazine poster" https://cdn.shopify.com/s/files/1/0358/7913/files/magazine_poster_12_08_14.pdf

Agreed. Wylde is.. Wild. Never heard of a pracical example that mixing of .223 Rem and 5.56 NATO has caused a problem, but with the Wylde you should be pretty safe.

Why not use the IPSC rules?

If I remember correctly, I actually picked this up this idea from the "Magpul Art of Precision Rifle", hosted by Todd Hodnett.. But I am not sure of the physics behind it either, so I agree on what you say about not making a blanket statement. However, I hope we can agree that: If the scope is level and directly above the bore (as in photo A), you will still get an error if the reticle isn't level in regards to gravity (unintended cant by the shooter). If you rely on the target background (the hill) and line that up with your reticle, you may be fooled to believe that everything is level in regards to gravity when it's not. Because of this I think a bubble level matched to the reticle can be useful on longer ranges, but I don't have any data.

I found the attached photo on an air gun site. "A" is what normally is considered the "holy grail", and you don't do anything wrong by leveling the scope to the rifle. But in my opinion "F" and "G" are also viable options, if you like having a canted rifle.Yes, you get a little different zero/ ballistic table, mainly in regards to side adjustment, which is illustrated in the video tunabreath linked to, but it's repeatable and you can hit consistently. What might cause problems, regardless of option A, F or G, is that you can get tricked by the terrain when shooting in the field. You may assume the hill you are shooting at is level, and line your reticle to that hill, while it really has an incline, and then your zero table doesn't match anymore. So I think a bubble level might be useful in the field, scope adjustments and gravity are the key words.

And here's a video of Teemu Rintala, 2nd place 2015 ERC.

There's no point in leveling your scope to your rifle, what matters is that the scope is leveled in respect to the horizon. Some long range shooters even cant their rifles significantly in order to get a better wrist angle, and that's no problem. Yes, your zero might be a little different, but as long as the reticle always remain leveled in respect to the horizon, the adjustments will be correct. I would recommend getting a scope level so you can ensure consistent shooting.

In Norway too we've had rifle shooters attend pistol matches, but with pistol caliber rifles only. They are scored as a separate rifle match however. I see your point, I'm just worried that too many divisions water out the sport, but it would be cool to see an evaluation. As for a pure rifle match, I think a pistol caliber is competitive on short range, but I see that it would lack at the longer distance (over 200 m?). Whats the problem of the IPSC target? Why do you americans keep holding on the the metric stuff, hehe?

You can compete in IPSC rifle with a pistol caliber carbine as long as you meet the power factor of 150, which shouldn't be a problem with a 9 mm AR. I don't see the point of introducing an own pistol caliber carbine division?

I suppose that's G1 BC and not G7?

I would like to do some long range shooting with my AR-15, and wonder what is the highest BC bullet that can be loaded to feed reliable from a magazine. Would the max OAL then be 2.260 in/ 57.4 mm? Affordable bullets would be nice also. My barrel is 1:8 twist, so it should be able to stabilize bullets up to 80 grains. Would it be a bad idea to also use such a load with a heavier bullet for 3 gun? I suppose the heavier bullets will have more drop.

Take a look at Bobby Johnson's iron sight setup. Does anybody have recommendations on a good clamp on front sight and a thin post?

Manipulation away from the trigger guard is a big plus, and is the reason I've never considered options like the BAD lever. The worst case scenario with such levers is that they may become a safety concern when you speed things up - I just don't like to monkey around the trigger when I'm not engaging targets. PDQ seems like the best option, unless it may cause failure to lock back or premature lock-backs (?)

Do any have experience with the PDQ bolt release (Pretty Damn Quick) from Teal Blue Bravo? The question is if it can snag and cause malfunctions. Anyone had problems with that? Seems handy for starts without a magazine, and for the "unload and show clear" command. Easier malfunction clearance is not that relevant, since this will be on a competition rifle (that is supposed to run, if it stops you're f*#ked anyways), but it's a nice bonus. But will it snag?

Stumbled upon the X-Treme Shooting Products Centra Goliath Front Sight, might be worth checking out. Has a 30 mm tube instead og 22 mm. http://www.x-tremeshooting.com/index.php?page=centragoliath http://www.brownells.com/rifle-parts/sights/front-sights/centra-goliath-front-sights-prod38268.aspx

Thanks for the link TonytheTiger. So Wilson Combat is out of the question. What's the hottest adjustable gas block these days? Will be running LMOS bcg and want to be able close it completely and adjust for different ammo. SLR Sentry? Syrac Gen II?

But how is it for those tough offhand shots, does it take a long time settle down and get a steady sight picture?

NIce, where's the balance pont and how does it feel on the long range targets? A little wobbly?

No problem buddy, these things happen on forums all the time.

That's what I said, rifle gas with 18" will be OK.

Think I'll build as lightweight as I can. Balance seems to be more important, but one can always add some weights front or back. I'll go with 18" because of the rifle length gas system, I don't think you can get any better than an 18" rifle gas tuned together with an adjustable gas block and lmos system. A little sceptic about rifle gas under 18", might get some problems with reliability.

Wish I could just buy a rifle and shoot, but I have plenty of time waiting for the purchase permit. Otherwise I really appreciate the input from all of you!

I've spoken with JP, and they say that both the 18" light and medium contour will hold 1 moa (often less), with the medium being slightly more accurate. They don't have any data on difference in heat dispersion. They did however say that the balance of the rifle will be more important, with most shooting a slightly front heavy rifle better (steadier sights, I guess). Sorry for all the nagging about dispersion on light vs. medium profile, but I think there might be a higher demand for precision in IPSC Rifle in Europe as opposed to 3 Gun in the USA. A common conception in Europe is that we often shoot long range at smaller paper targets, while in the U.S. larger steel targets are used. Paper targets don't provide any feedback, so you need to call your shots and trust your equipment. Many of the good IPSC shooters I've spoken with are proponents of somewhat heavier barrels, medium contour being the "minimum", but I want to challenge that by looking at data. Lets take an example on what accuracy that's needed in IPSC Rifle: The A-zone of the IPSC Classic target (smaller than Metric) is 15cm (6") wide, the whole target is 45cm (18") wide. At 300 yards (275m) the 6" A-zone will be 2 moa, while the whole target (18" wide) is 6 moa. Assume only Alfa is good enough. Then move out to 350 yards (320m), probably will never encounter longer ranges than that in IPSC. At 350 yards the 6" A-zone will be 1.7 moa (if it was 7" it would be 2 moa at 350 yds). While there seems to be no data on heat dispersion available, my impression is that different barrel contours will be negligible. (Would very much welcome data, though). It seems like the rifle's balance is more important, and now I'm just worried that the 18" light contour (shaving off 0.5 lbs/ 9 oz/ 250 grams compared to 18" medium contour) will be too light coupled together with the ultra light AP Custom handguard (also shaving off 250 grams compared to the 15.5" JPHG3-6M-RC handguard), thus moving the balance point a little too far back. Will be running a Swarovski 1-6 and ACE ARFX stock. Of course the balance will be a lot of personal preference, I just want to hear what you guys think.

Seems like there are many myths and little scientific data on light vs. heavy barrel accuracy. Some say skinnier barrels have come a long way, perhaps outperforming some old heavy barrels, but where's the data? Heavier barrels will typically be less affected by heat, but in theory a lightweight barrel that's concentric and stress relieved should be almost just as good. Thats the theory, but then there's always the real world. And of course you can get shitty heavy barrels too. When testing accuracy, groups opening up could just as well be the shooter getting tired and losing concentration, anticipating shots, etc., which can happen to even good shooters. To remove as many human factors as possible, a test should be conducted with a rifle bolted onto a machine rest, like mentioned in the ar15.com post. Then we would be able to see some example of differences in the mechanical precision. Then set up a camera by the paper target to see where the rounds go, and measure the group afterwards. - First 10 shots fired with with 1 minute intervals to let the barrel cool down in between - Then start blasting 50-100 rounds with just seconds in between to get the barrel warm Compare some different barrels, and that would give us some scientific data. Even if renowed manufacturers might have some good and less good barrels within each batch, I think we would be starting to see a trend.