Leaving aside that the true limit will be obtained by real practice what would your experience (or prejudices [img]images/icons/wink.gif[/img] ) lead you to say the outer limits of range would be on game for:-
Bullet - 0.458BC,
MV - 3,050fps
Accuracy - 0.5" for 3 at 100yards
Zero - 1.5" high at 100yards
Scope - 6x reticle subtending 0.43" at 100yds (ie fine)no field adjustments
Quarry - antelope/goat size of a vitality that retained energy of this combo will kill past range guide would allow shooting.
Habitat - mountains
And what would be the single equipment thing that would allow shooting at greater range?
You can get a little more "point blank" range by zeroing higher at 100 yards, say about 2.5 inches vice 1.5" (should put your point blank out to about 300 yards vice about 265 at +- 3") (I assumed sea level (water goats), 59f degrees and a scope height of 1.65".)
Use a taller set of scope rings. A 3" tall set of scope rings will allow you to keep a 1.5" high 100 yard zero and still have a point blank of 3" out to 300 yards. Not a likely setup but interesting, remember those see-thru mounts.
Use a scope with a duplex reticle and use the top of the lower thick duplex as a secondary aiming point, easy to do but range need to be verified before changing Point Of Aim point(s).
In addition to Dave's points. With that kit I think my absolute limit would be 300m; my comfort zone would only be out to about 230m.
Your rifle specs wouldn't be the limiting factor; the scope would. -for 2 reasons:
Firstly I think aim-off for elevation & wind would be nigh on impossible to do accurately with a standard 6 power scope beyond that range (unless one were to subscribe to the 'spray and pray' school of thought!)and, secondly, a 6 power scope would make it as much a test of my visual acuity as my shooting skills!
Therefore, IMHO ( [img]images/icons/smile.gif[/img]) the single greatest improvement you could make (assuming you already have a laser) would be to get a more powerful scope.
(BTW, I have found that the more 'traditional' Brit stalkers (and I get the impression from your posts that that may include you [img]images/icons/wink.gif[/img] tend to shy away from 3-12 scopes (and are simply aghast at the thought of a 4-16!) in the same way that they shy away from bipods...until they try them!)
Recommendation: 3-12x50 S&B PM1 sniperscope (which has a 30mm tube unlike the 34mm PM2s)(the sportsman do them for around £750 last time I looked) or a 4-16mm precision hunter (again 30mm tube but now with parallax adjustment). PM2s are better again , but a pain to mount on a sporting rifle if you don't like Apels.
Wow, that turned into a sermon. Apologies for that; but I hope it provides food for thought!
Interesting question. How much does that bullet weigh? I agree with Dave on the zero range. I would think, without further info, that 500 yds, if not more, would be do-able if your bullets have enough energy at that range. Personally, I like a little more scope. I would suggest that the "single equipment thing" should be a laser rangefinder. I would also suggest considering an anemometer. I am using a $16 Dwyer from Sinclair that works pretty well.
Location: The rifle range, or archery range or behind the computer in Alaska
Re: Range limit for this equipment?
I would say the single most peice of equipment that would extend the range would be a Mil-Dot reticle. This way you can range game and have points of referance for longer shooting.
If the set up you describe has bullets of adequite weight, I would say the max range would be 400 yards and pushing it for a non adjustable scope with no reticle points of referance aside from the crosshair itself.
With the addition of a mildot or npr2, you could easily and reliably measure range and aim point to reach out to 700 yards and more if one took the time to really practice ranging with this method.
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
As you didn't list the bullets weight i ran the numbers with a 150 gr bullet using G1 drag co-efficient common to spitzer style hunting bullets.You will be 303 inches low at 1000 yards and have 596 lbs of energy which is low in my books even for thin skinned Antelope which die very easily once hit.This factor would lmit me to 600 yards.A cheap rangefinder at $330 takes the guess work away and a scope with a few drops of fingernail polish to give you pre-set up distance marks is a very desirable thing.I would sight in 4 inches high at 100 and put a drop of fingernail polish on your scope for 400,500 and 600 yards leaving 0-300 alone.Most goats are killed with the first shot or never killed at all and most shooters hold to high by not knowing the correct distance so they hold high.Sight your gun in as mentioned and put the dot on the front shoulder until you get past 350 yards.