Is TR actually behind Open, anymore?

[davidjoe]

There are three possible ways that TR may be hamstrung relative to Open, but which of them is actually true, and/or by a material amount, when we shoot for score, not group?

1) the cartridges cannot compete in the wind;

2) shooting off a bipod is inferior to shooting off an Open rest,

3) a heavier TR rifle could shoot better than a rule-compliant one.

So, why the curiosity, because TR leaders at 600 and 1,000 are really closing in on F-Open scores, despite the limitations. We in open push our barrels more for life into flyers, deal with heat induced vertical, and haven’t had quite the bullet revolution that TR has over this generation.

The two TR cartridges are tagged as if it’s stock cars versus F-1, but if the cartridges were not shot from from a significantly lighter rifle, or from a bipod, would they have “closed in” even more?

The thought experiment now in metal are two Open-weight rifles, organic open weight, reached from unaltered parts.

TR rifles are not ~4 pounds lighter, they are 4 pounds plus whatever their bipod weighs, lighter, which is 26 ounces in the case of the excellent Phoenix. My personal theory is that this fact, not the cartridge itself, is really the only thing keeping TR at bay.



The Blue gun is 21 pounds 14 ounces with its Phoenix. It’s a .223 with a straight 6.5 twist to shoot the heaviest .224’s made, which is now 95 grains. Plan is to HBN coat SMK’s and compare them to uncoated and to others at midrange. 1950’s-ish 40-X with a Krieger 4 groove that is 29.75” from the face of the receiver.



The Red gun is a 22 pound 1/2 ounce .308 with a 5R Krieger 10 twist. It’s a 1.45 MTU style barrel tapering to a 1.0 like I run in Open on a Surgeon XL that itself weighs 4.5 pounds. If there is a proven stock on the front rest sand bag open game it’s this Z-Rail Kestros. This gun will start and maybe stick with the 200-20X.



I have run 1000 yard drop charts that show a typical .284 with 180 hybrids drift is actually closer to a contemporary TR rifle’s (200 hybrid) than it is to an aggressive RSAUM’s drift with 195’s. Yes, the split is close to even, but leans toward the .308.

At match after match the magnums are certainly not assured of beating the .284’s, and so by this same token, the question is begged of how would they compare with a .308 that was shot from an equally heavy gun, off a front “rest” that certainly warrants that name.

I look at it as club match experiments to see where they would shake out if in TR, and of course where they do shake out in open.

 

[Falfan2017]

It would be interesting to see the 308 limited to Palma 155 gr bullets to make a bit more difference In ftr and open.

 

[davidjoe]

Yes, especially because the COAL and pressure attained don’t really resemble a true Win .308. But, I guess that’s TR’s little slice of “open” license.

The main reason these guns max out is they have the heavy and comfortable rear that is basically impossible within TR weight when a preferred contour is also used.

 

[MikeMcCasland]

I'm a big believer that the main thing "holding TR rifles back" from routinely scoring with the open shooters is the weight/rest aspect. At 600, that's especially the case; they'd basically be equal so far as I'm concerned.

That said, there is undoubtedly a cartridge element to it, which doesn't seem to become terribly influential until you're shooting 1,000 yard in "big wind". That's the only time (in aggregate) you can see the 7mms / big 30s hold a ring plus advantage.

In some 1k club matches, I think you probably could place (or win) using a .308 setup in an F-Open configuration. National/Regional level matches, I suspect anything that even introduces the added potential of losing a point makes it almost a non-starter.

Us FTR shooters like to make mention every time a TR score gets up into the F-Open ranks at big matches, but at 1,000 that's still pretty infrequent...even when it's somebody who is known to have perfect form, and regularly scores well at the national level.

 

[davidjoe]

Mike, there’s a “numbers theory” question related to what you mention towards the end, in a large score sample of matches, do TR and Open score differently as divisions by exactly the difference that would be suggested by the circular error probable of the two “effective BC’s on target” if never trying to cal the wind, and simply shooting.

My thought is that the .308 correction at 1,000 is getting close enough to a .284’s that more and more TR will be able to overcome the extra call, (typing when born with nine fingers, TR is functionally as if the wind is always stronger, or, the line is further back than open’s is) and still snag the 10 ring. The Open scores will improve in x count but the point aggs will keep getting closer. Guys don’t want to push the 30 mags any harder these days because of barrel life or diminishing accuracy returns. 7 mags can’t go faster and stay together. Open may be near the point of just becoming a better wind caller, game.

 

[kzin]

I asked this question several years ago when I came on board.
The answer was overwhelmingly the cartridge/ballistics.
It will be interesting to see if consensus has changed at all.

 

[Ned Ludd]

I personally have a different opinion. The differences in scores between F-TR and F-Open are not primarily due to the weight limit of the rifle setup or the front rest, but rather are largely due to the ballistic advantages offered by F-Open calibers. Using the same general set of atmospheric conditions for both, a 7 mm 180 Hybrid at 2800 fps (common .284 Win F-Open setup) is predicted to enjoy a ballistic advantage over a 200.20X at 2650 fps (common F-TR setup) of ~0.5 MOA at 600 yd, and 0.9 MOA at 1000 yd. Those are HUGE differences in external ballistics. Although I have little doubt that for some, felt recoil and gun handling may be improved with the heavier rifle and a solid front rest, there are plenty of F-TR shooters that seem to do just fine from a bipod. The primary reason I believe the ballistic advantages of Open calibers represent the lion's share of the difference between scores in the two disciplines is that when conditions are calm or mild, you will often find the F-TR scores are very close, if not equal, or sometimes even better, to those posted in F-Open. When the wind conditions are challenging, the top F-TR scores typically lag noticeably farther behind the top F-Open scores. That suggests to me that external ballistics of the calibers used makes up the larger part of the difference in scores between the two disciplines, rather than differences related to gun handling.

 

[XTR]

I agree with Ned here. There are times when a TR shooter can out shoot many open shooters, and to some extent I think that happens when the winds are nibbling and the Open shooter is more likely to rely on BC and the TR shooter adjusts. Scores when the wind kicks even the best of us (F-TR) have a hard time putting up scores in the top 1/3 to 1/4 of the Open field. You can see this at big events like SWN and the FCNC.

in the final fraction of an MOA in pure precision, yea, the 22lb open gun on a rest probably gains some, but the difference is small.

 

[lawman29]

One simple observation provides the answer:. How many.308s do you see on the F-Open line? "0"

 

[davidjoe]

I'm a big believer that the main thing "holding TR rifles back" from routinely scoring with the open shooters is the weight/rest aspect. At 600, that's especially the case; they'd basically be equal so far as I'm concerned.

That said, there is undoubtedly a cartridge element to it, which doesn't seem to become terribly influential until you're shooting 1,000 yard in "big wind". That's the only time (in aggregate) you can see the 7mms / big 30s hold a ring plus advantage.

In some 1k club matches, I think you probably could place (or win) using a .308 setup in an F-Open configuration. National/Regional level matches, I suspect anything that even introduces the added potential of losing a point makes it almost a non-starter.

Us FTR shooters like to make mention every time a TR score gets up into the F-Open ranks at big matches, but at 1,000 that's still pretty infrequent...even when it's somebody who is known to have perfect form, and regularly scores well at the national level.

Mike, the last Texas state 600 championship agrees with your thinking.

 

[MikeMcCasland]

I want to clarify my statements because I've re-read my earlier post and I don't think I articulated my position correctly. Please accept my apologies, I'm just an idiot who drinks a lot of caffeine and posts dumb stuff on the internet.

Essentially I'm in agreement with XTR and Ned.

Net/Net - It would be easier to put up high scores in a rest/heavier configuration, however there is undoubtedly a major advantage in shooting a .284/300WSM etc.

I do think in MR there is less of an advantage, and in some very limited circumstances the "line breaking" capability of the .308 can offer an advantage over some 6mms found in Open.

 

[Turbulent Turtle]

The difference I see between F-TR and F-Open is about 300-400FPS for the same BC bullet.

 

[XTR]

....I'm just an idiot who drinks a lot of caffeine and posts dumb stuff on the internet....

I’m going to steal this.... just sayin’

 

[davidjoe]

.... when the wind is big, TR lags, that is. We must have had a lot of wind because even at 600 there was a significant difference in scores.

The 20 shot records at Bayou are very close between TR and Open, though.

 

[MikeMcCasland]

.... when the wind is big, TR lags, that is. We must have had a lot of wind because even at 600 there was a significant difference in scores.

We did. That was sustained 20mph, gusting 30mph. I remember holding target frames still while sling was shooting, and I remember my TR rig literally rocking in the gusts.

Look at the team scores from the day prior. Calm conditions...the winning TR team was off the winning open team by 1 point...and that open team was stacked.

 

[davidjoe]

Ned, your drift differentials are what I came up with as well. It’s definitely material. There’s more headroom afoot in TR than open though, I believe. Probably 6 new bullets over 200 in the last 2 years, including Berger, but put them in Open and accurate round count is unbearable (or the recoil is thought to be).

XTR had posted with me last year on H1000 and the 250 A-Tip. If you run a chart on it at 2,450 FPS it beats or at least equals the .284 at 1,000, which is an attainable speed. Back then, no one had yet put A-Tips to work but by now there is at least one open 190 shooter who is extremely hard to beat with them.

EDIT, H4350 was the powder that was used to reach that speed, not H1000.

 

[Jennb]

After recently winning a mid range match shooting open with a .284 Shehane, close to open weight rifle but using a total FTR set up with XIT stock and a Duplin bipod. It is my opinion that the caliber and bullet availability of open rifles is what dominates their class.

For someone who is used to handling a bipod and the recoil of a .308 a tripod open front rest might have given me a tighter group and a few more X’s but a 448 out of 450 with 35X’s in crazy winds was not too shabby.

I can tell you for sure that my wind holds would have been much different for my .308. The extra weight of the rifle kept the recoil more manageable for the caliber but on an open rest recoil would have been less to deal with because of the difference in handling the rifle. No hop to deal with and getting back on target with an open rest is much simpler.

When all said and done TR is sneaking up on Open score wise because we are getting better at handling our rifles and learning more about reading the wind. We have been shooting the same weight of bullets with similar ballistics long enough that we have settled into a groove.

 

[Rope2horns]

I heard the type of carpet makes it a Open gun.

 

[davidjoe]

I heard the type of carpet makes it a Open gun.

... and if you are shooting for prizes in each division, if Jenn is there in TR, I’d suggest using that carpet.

 

[dnellans]

I personally have a different opinion. The differences in scores between F-TR and F-Open are not primarily due to the weight limit of the rifle setup or the front rest, but rather are largely due to the ballistic advantages offered by F-Open calibers. Using the same general set of atmospheric conditions for both, a 7 mm 180 Hybrid at 2800 fps (common .284 Win F-Open setup) is predicted to enjoy a ballistic advantage over a 200.20X at 2650 fps (common F-TR setup) of ~0.5 MOA at 600 yd, and 0.9 MOA at 1000 yd. Those are HUGE differences in external ballistics. Although I have little doubt that for some, felt recoil and gun handling may be improved with the heavier rifle and a solid front rest, there are plenty of F-TR shooters that seem to do just fine from a bipod. The primary reason I believe the ballistic advantages of Open calibers represent the lion's share of the difference between scores in the two disciplines is that when conditions are calm or mild, you will often find the F-TR scores are very close, if not equal, or sometimes even better, to those posted in F-Open. When the wind conditions are challenging, the top F-TR scores typically lag noticeably farther behind the top F-Open scores. That suggests to me that external ballistics of the calibers used makes up the larger part of the difference in scores between the two disciplines, rather than differences related to gun handling.

Ned - can you provide more details on you come up with this number for advantage? is it the improved horizontal distribution in a fixed constant plus variable distribution of wind? e.g +- 2mph from 10mph?

having less total wind to hold due to improved BC is convenient, but doesn’t in and of itself improve distribution.

i’d like so see how others are doing the math on ballistic advantage.