7.21 Firebird

well that's great, but this topic isn't about you, it is about a loud mouth idiot who had his 4200 foot per second bullet 14 inches high for a 300 yard zero :jerkit:
 
Stubblejumper, i think mr bartell is trying to say that these guys, like the one mentioned by the original poster, make fools of themselves with megamagnums. Guys like you, who practice regularly and know there weapon only make up 5 % of the guys who shoot such guns. I tend to agree with him, and good on ya for knowing your tools and using them to there potential.
 
well that's great, but this topic isn't about you, it is about a loud mouth idiot who had his 4200 foot per second bullet 14 inches high for a 300 yard zero

The topic started out about the idiot with the lazzeroni,but you made the statement below which opened up another topic.

a guy has to wonder what real world advantage there is to pushing a 140 grain bullet past 3200 fps

My reply was to that statement,and the fact that some people can take advantage of the additional velocity.
 
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fair enough

but in the same sense, a well trained shooter, with a laser range finder, probably wont kill any more game with a 7.21 Firebird, then they could have with a 7mm Rem Mag, or a 280 Improved, etc
 
Velocity won't reduce drift anywhere nearly as much as going with a heavier bullet, even at relatively short range. And a heavier bullet will retain more energy much farther out as well. In fact, velocity has only a very negligible effect on drift, all else equal.

Velocity also has a rather limited effect on 'flatness' as well, at least once we start talking about intermediate and long ranges. The difference in what people call 'flatness' or 'point blank range' (the distance to which you will be able to hit an 8" target by holding directly on it, i.e., no more than + or - 4") between an STW at 3500fps and a 7mm RM at 3100fps is only about 35 yards (or about 10% further)

However, with a laser range finder, flatness isn't even a concern (if you know the range, you can hold over or use your mil dots effectively.)

The advantages touted by the mega magnums really are only 'paper' benefits, even when we start talking about shots that are extreme long distance shots under field conditions (under controlled conditions, 500 yards is only intermediate range).

I like big magnums. I own and use them (though I tend to lean towards bigger diameter as opposed to greater speed). But I sure as hell don't believe the I 'need' them, or that the edge they afford me is much more than psychological.


I totally hear what tod is saying and agree. If you have the skill to make 500 yard shots, the differences between the ultra magnums and something like the lowly 308 won't make much difference to you. Once we're past 400 yards with ANY cartridge, wind and drop are MAJOR factors and much be compensated for much more with with skill than speed.
 
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I was very tempted to nail one of his water jugs with my Sako 7mm Rem Mag...but hey....my 160's were only doing about 3100......I couldn't even compete......

trajectory is a wonderful thing...if it weren't important we'd all be shooting 44-40's.....

this whole thread has me checking out 7 STW & RUM ballistics.....maybe I'll see if the local 'smith will lend me his STW reamer.......I could try that first...a factory blued Sako barrel aint worth spit anyway......

stubblejumper.....what I think is a lot of shooters really wish they had the time to get to know a rifle and load as well as you have and make 400 yard+ shots seem routine....no reason for them to jump on ya....I'm convinced it's part envy and part lack of exposure and information.....

hmmm...STW or RUM......the RUM might be a waste in a 24" tube....but I did once see a 24" STW peg the chrony at a solid 3400 with a 139 Hornady.....
 
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Velocity won't reduce drift anywhere nearly as much as going with a heavier bullet, even at relatively short range.

To test this theory,I plugged some numbers into a ballistic calculator and the results were.

140gr accubond at 3200fps(typical 7mmremmag)

wind drift with 10mph wind 400 yards-9.9" 500 yards 16.1"

160 gr accubond at 3000fps(typical 7mmremmag)

wind drift with 10mph wind 400 yards-9.8" 500 yards 15.8"

Going to a heavier bullet,both driven at maximum velocity improved wind drift by only .1" at 400 yards,and by only .3" at 500 yards.

Then we increase velocity by stepping up to the 7mmstw

140gr accubond at 3500fps

wind drift with 10mph wind 400 yards- 8.8" 500 yards 14.2"

The reduction in wind drift was 1.1" at 400 yards and 1.6" at 500 yards.The reduction in wind drift was much greater by increasing the velocity of the 140gr bullet than by simply using a heavier 160gr bullet of the same design.Theory proven incorrect at 400 yards and 500 yards!And you did post "even at relatively short range".

Now if you are talking 1000 yard target shooting,a heavier bullet does have significant advantages,but not for hunting out to 500 yards.


Once we're past 400 yards with ANY cartridge, wind and drop are MAJOR factors and much be compensated for much more with with skill than speed.

Bullet drop is easily compensated for if you have a laser rangefinder to measure the exact range.However,no instrument that you can easily carry,can measure wind direction and velocity all the way to the target.As such reducing wind drift is always an advantage.
 
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then why are you using 140's?
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Wind drift for 140gr accubond at 3500fps

400 yards-8.8" 500 yards-14.2"

Wind drift for 160gr accubond at 3250fps

400 yards-8.8" 500 yards-14.2"

No difference at all in wind drift to 500 yards when both are driven at maximum velocity in my rifles.

I will not shoot past 500 yards on a game animal,so that is the maximum distance that I used for wind drift.

Trajectory wise,the 140gr bullet shoots flatter in my rifles at 500 yards at the velocities posted.

Accuracy wise,both of my rifles shoot 140gr bullets much better,so the choice is an easy one.
 
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hmmm...STW or RUM......the RUM might be a waste in a 24" tube....but I did once see a 24" STW peg the chrony at a solid 3400 with a 139 Hornady.....

Either is a waste in a 24" barrel.Both require at least a 26" barrel to reach their potential.
 
LOL your right none, because you loose all accuarcy and really!

Apparently you didn't read what I posted previously.

80gr of imr7828 in either of my 7mmstws gives me 3500fps with a 140gr bullet with groups averaging 1/2" to 5/8" depending on the bullet.

The accuracy that my rifles deliver is better than most rifles using much slower cartridges.
 
...saw a guy with one at the range today......"4200fps with a 140"...so he says..so I said he must have a long barrel like about 30"...nope..."just 28", that's all you need"....I'm sure it was 28" with the brake....but he couldn't hit a 500ml bottle of water at 100 yards...."I have it sighted 14" high at 100 so it's right on at 300"........I don't need software to tell me this doesn't jive with a 140 at 4200....or even a 140 at 3300...no I didn't offer to let him run one over my chrony
......why do I even go to the range this time of year?.....

I know what you mean, Rick. ;)
 
Either is a waste in a 24" barrel.Both require at least a 26" barrel to reach their potential.

I generally agree, but I have a 24" STW. It manages 3200 fps with 160s (only with RL25 though, it's a fussy bugger). I haven't really done much load work with 140s, I prefer the heavier bullet for LR elk and moose. I've tried a 7 RUM, there really isn't a whole lot of real world advantage over the STW (which in my experience, admittedly somewhat limited, is the more accurate of the two, must be the belt, LOL). FWIW - dan
 
The last STW I had built sported a 1-10" twist 27" Pac-Nor tube and would make 3550 with the 140 and 3300 with the 160 Partitions. Both would stay around ½ moa right out to 600 yards. Wonderful long-range performance, but most of my hunting did not require that I exploit it's potential, so I sold it to someone who hunts open terrain a lot more. He loves it! But as Stubblejumper already said, it requires practice and familiarity to make use of such potential. Regards, Eagleye
 
Cronys don't lie and when I was working up my 200 grain Accubond load in the 300 RUM and more powder than 92.5 grains of Retumbo actually slowed the bullet down and made big flame out of barrel....show good....accuracy and velocity bad. I load 92 grains of Retumbo and get about 3100 FPS with the muzzle break and excellent accuracy. I was considering a 7mm RUM but see no advantage over the 300.
 
You know, I just don't get all this ultra-high velocity stuff. The truth is that when you get past 350 yards, you have to elevate the rifle and read the wind. Period. It doesn't matter what kind of super magnum you use.

Stubblejumper's experience is excellent, and my hat is off to him. But his ballistic comparison was telling. His 140 grain load from the STW beat a 7mm Remington Magnum in wind drift by just less than two inches at 500 yards. I just spent three weeks this summer shooting with the world's best long range shooters, and I can tell you that it's a rare person indeed who can hold accurately enough to see a two-inch difference at 500 yards -- especially in hunting conditions. Far more important is the ability to actually read the wind and adjust accordingly. Therefore, the actual, real-world "advantage" offered by the STW load is more a fantasy than anything else.

More important than everything else combined, (assuming world-class wind reading and shooting abilities on the part of the trigger-puller) is the long range, consistent accuracy of the rifle itself.

At the World Long Range Championships, we were shooting .308s with 155-grain bullets at 700, 800 and 900 metres in brutal winds. I shot with David Luckman at 800 metres (880 yards) on Day 2 and saw him shoot a perfect score. He shot a lot of perfect scores in that match. (By comparison, the only perfect score I managed was one morning at 300 metres.) I repeat: this was with a "lowly" .308.

If you have to elevate and dope the wind, anyway, who cares if you have to move 3 minutes or 4.5? It's just a number. The key is having the skill to read the wind and having a rifle that will consistently put the bullet where you want it to go. I can tell you one thing, if I honestly had to do serious shooting at 500 yards, I'd probably want to use my "precision/tactical" .308 built around an old BSA action wtih a Krieger barrel because I've used it in competition and I know how it performs at extended ranges. It's way more reliable and consistently accurate, shot after shot, string after string, day after day, than any hunting rifle I've ever fired.
 
If you have to elevate and dope the wind, anyway, who cares if you have to move 3 minutes or 4.5? It's just a number.

There is a huge difference in judging wind on a range with wind flags than in many hunting conditions,especially those involving creeks,or hills.The less that a bullet is affected by wind,the less that you have to allow,and the less the chance for error.
 
Just for the record, my current STW does 3300 fps with 160s out of 24". Might be a fast barrel, I don't know, its the same load I used in my other ones. Brass life is good and no pressure problems. I was going to rebarrel it to 375 but when I started shooting it I found it shot sub MOA out to 300 yds. Flatter is better but it still doesn't make for ultra long range shooting. I took my first Deer this year at quite long range only because there was no way to get closer. I could have made the shot with an 06. Either you know where your guns balistics or you don't. The Lazeroni guy is obviously an idiot and has no clue.
 
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