I am sorry but this is riddled with lies.
Firstly the crossbow pictured and descibed by Steve is not a 25 year old barnett panzer. I know this because I own and shoot two of them.
There are pictures here of a Panzer or a Chinese copy.http://fotoblog.in/clanek/419
I also own the Chinese copy. You can tell the two apart because there is a barnett logo on the bottom of the grip on the real one.
There is little in function between the original and the Chinese copy, the aluminium is slightly lighter and the dimensiosn of parts are marginally smaller.
Now there is nothing special about the panzer. It is a fairly bog standard 150lb crossbow. It will generate somewhere between 215FPS and 250FPS depending on the condition and the bolt tpe and grain weight.
The trouble is the rest of the comments relating to crossbows here are mostly bull with some cut and paste google facts thrown in.
"I have a great time with my little Barnett Panzer, and have eliminated a couple of pests on my 300 Meter Silhouette Pistol Range in Eastern Washington"
Not unless they were the size of elephants.
At 300 meters the bolt has dropped so far below your sight window that you would hate no hope of hitting a one foot square target consistently. Up to 50 meters, sure, 100 meters, maybe if you *really* know what you are doing, 150 Meters if you have a bow your built and know what you are doing. 300 Meters? Just not possible. Complete nonsense.
"I can attach broadheads to these bolts, and have a quiet shortrange weapon"
OK so crowwbows are supposed to be silent?
Compele nonsense - they are noisy. This is a myth. The noise is sufficient to make will animals jump and run, which is why you should never shoot a crossbow at a living animal unless very close, the bold may end up maiming it if it jumps at the sound.
There are several 'devices' that attempt to silence crossbows but they also slow the FPS.
As with longbows tuning for crossbow broadheads is a challenge and quite difficult, in my experience 2 blade creates the best effect but feel free to experiment.
Finally if you have indeed in a moment of madness decided that you are going to use steel wire as a serving on a kevlar or dacron based string, please stop before you loose an eye. Strings are cheap. I have in one third world country seen a piece of nylon washing line installed on an old barnett wildcat but unless you are re-enacting 'the road' there is very little reason not to just buy 50 bucks of strings and forget about it.
The rope cocking device pictured is just that a rope cocking device. You can get one on ebay for very little. It is not improvised.
However in terms of accuracy it is absolutely critical that the string be drawn exactly without any additional pressure to the left or right of the limb when it is cocked. This is the advantage of a goats foot. I own a barnett model which is no longer made, an ugly thing in white aluminium. Similarly cant is an accuracy destroyer and a spirit lever is a good extra. Scopes and red dots are fairly pointless. If you can't see 60 Meters then a large moa glowing red dot is certainly not going to assist you.
Archery clubs do not like crossbows. There is a good reason for this, they destroy arachery butts very quickly. A croosbow shooter may do better looking to a gun club in many countries and places.
This is probably the biggest problem a beginner crossbow shooter will have, bolts are expensive and easy to ruin unless you get a good backstop that preserves them.
2119 aluminium arrows may be used for bolts for 150 lb crossbows. There is little or nothing between the cheaper models and their chinese copies and even in the case of the more expsnive bows very little practical performance gain. In essense you will have a maximum accurate range of 60 meters and something that delivers the same FPS as a compound bow. They are noisy and expensive to run in both strings and bolts. Arachery tools are useful and quite cheap, get a scales that measures grains, an arrow cutter and a fleteching jig.
There is great depth to archery and most interesting results come from great care in bolt and arrow design and tuning. If you want to get the best from your bow focus on this.
I could go on....but readers should just take heed that there is much wrong with the stated facts and I am under the impression that this was written by someone charged with enthusiasm for a new toy who got a little carried away and feigned experience and with a pinch of wishfull thinking and fantasy thrown in for good measure..crossbows do not go 300 meters and are not silent and are no better than a compound bow in results. Love the things and wish they could do more but they can't, I've been shooting them for 20 years and have 7 of them hanging on my den walls as I type, along with a bunch of recurves and some compounds.
Quite happy to continue the thread and get into real detail on crossbows, archery, stone bows etc for those who are enthusiasts.
About the only really practcal use for a modern 150 LB is ambush hunting from a stand at short range using a bait. As a weapon it is pretty useless unless you are planning to ambush people, which I would hope you are not. Very little hope whatsoever of hitting a running target at 50 non of hitting reliably at all at any distance in excell of 100M unless you are playing at clout shooting.
DO NOT USE STEEL WIRE ON ARCHERY STRING SERVINGS OR YOU COULD BLIND YOURSELF.