Have you heard of the 17-06 Schneider?

[Marco]

i was reading an old SSAA magazine (australian shooter sept 2005) and i found an article on page 54 thats titled " When the bug bites" and is about wildcats and improved cartridges, anyway yada yada yada and onto page 60 theres a photo of a " .17-06 Schneider " YES it looks like a necked down full length 30/06 case to 17 cal, anyway theres no more about it anywhere in the article, just the picture and the picture description above it.

have you guys ever heard of it as i cant seem to find anything of it on the net either, however about a year ago i posted something in saubier about it, but they all thought it was a load of BS.

if you guys have heard of this wildcat please post a reply, all i know that for a cartridge thats BS the picture looks very very impressive.
ive been looking at the picture while typing this page and one day
hopefully see 17-06 fly.

Marco

[trevort]

yes

You planning on building one

Think the term that comes to mind is "overbore"

[Marco]

yes

You planning on building one

Think the term that comes to mind is "overbore"

ok trevort so you know something oh please do tell.
am i going to build one , firstly i want to know more about it thanks

[Con]

Think the term that comes to mind is "overbore"

trevort,
Question for you ... or anyone else. In 17cal ... how big would the case have to be to work with Reloder25 or the other ultra slow powders?
Cheers....
Con
PS: Serious question too ... the 17Rem is said to be overbore but works with AR2208/9 ... if you used a slower powder ... could we get away with a 17/06? Funneling large charges (relatively)
through small bores wont do barrels much good.

[Aussie steve]

I wonder if there is a powder on the market that is slow enough for it? 60 odd grains of powder in that very small bore, I think that even Re 25 might be too quick? The .17/250 might be a better choice, the .20/250 is said to run on Re 19 and Re 22, so Re 25 might work in the .17/250?

Still if you go ahead and decide to build it please let us know what velocities you get, and if you got it sighted in before the barrel

Steve

[Marco]

what do yars mean by overbore?

[GriMo]

Not sure if its a fully defined term but what i have found to measure overbore is a combination of bore surface area and catridge capacity in water. Have borowwed the below example from http://www.reloadingroom.com/index_files/Overbore.htm as i belive it explains it better then i can



In a .17-cal cartridge, the largest case not overbore will have a capacity of about 29 grains of water. (.172 x .172=.0296. Then slide the decimal place to 29.6) Cases that hold more water will certainly be faster, but they are not gaining that speed efficiently. The 17 Remington holds about 26 grains of water when full. (We will disregard the space lost by bullet seating, since that is a variable out of our control.) The wildcat 17-223 wildcat holds almost exactly 29 grains of water. All other common rounds in .17-caliber have smaller capacities, which helps to explain why .17-caliber wildcats on larger cases are uncommon: they are wildly overbore.


so, times the bore diameter by itself and move the decimal place down 3 places. If the case holds more water then that number its overbore. Also gives you a number to compare how overbore something is. assuming the 17-06 has similar capacity to a normal 30-06 you end up with a massive overbore situation. Without a massivly long barrel really your just making a flame thrower that pushes a pill out infront of it.

A different website i was looking at recently had a formula to give a comparative index. using the above figures the 22-250 is slight overbore approx 1100. The 17-06 comes in at a toasty 2300

[Dary]

A different website i was looking at recently had a formula to give a comparative index. using the above figures the 22-250 is slight overbore approx 1100. The 17-06 comes in at a toasty 2300

Could you please provide the equation for the above math or the name of the web site you found it own?

[GriMo]

SUre mate, just divide the case capacity in H20 by the squared diameter

[Dary]

Thank you!

[trevort]

Marco, I've heard of it and seen pictures but thats the limit of my knowledge. My 17 experience is hmr and mach4

[Marco]

ok ta for all your answers

[Tony Z]

This term overbore is a little maligned in some instances. Inefficient would be a better term i would think. This is mainly due to a powder not yet developed to suit that purpose. The 243 got a very bad image in its early life as being somewhat overbore until modern powders were developed that made it more user friendly and did away with its SEE reputation. The 25/06 is another that had a similar start and it wasn't until years later and the development of better propellants, that it too lost the same reputation the smaller 243 had. Remingtons 7 MM Magnum is another that had a bad rep years ago. All three of these cases are now not even close to what has come out since. The Lazzaroni cartridges are a classic example of proprietary cases that are way beyond what was long ago considered overbore. The WSMs in the smaller bores are another group that are way beyond the overbore cases of the past.

Years ago a 30/06 Ackley or thereabouts was considered about optimum for a 30 cal and somewhere along the line Ackley stated that a 30 Magnum was a waste of time. Now with the advent of far more efficient and cleaner burning powders, 300 Win Mag may be considered optimum. There was a scale around years ago that had the efficiency rates of cartridges listed where a case was graded on efficiency of powder used and its net fps gain per grain of powder. This ratio was somewhat unrealistic as with the bigger cases and heavier bullets with slower powders in longer barrels, this efficiency rating altered. For example a 30/06 AI that had a barrel length of 24 inches and used 60 grains of Re22 would launch a 200 grainer at just a tick under 2800 fps. This powder delivers optimum performance in this case. The 300 Win Mag with the same bullet fired in a 24 inch barrel would net about 2950 fps with 72 grains of the same Re22 which is also the optimum burn rate for this case. So the Win Mag uses 20% more powder to gain 5.5% more velocity and at first glance one would assume that it is overbore and somewhat inefficient. BUT, add 6 inches of barrel to the Win Mag and that velocity suddenly becomes 3100 fps for a net gain of 300+ fps over the AI or about 11%. So you can see that the ratio has somewhat altered. The 30/06 AI with the same 30 inch length barrel will increase its speed as well, but it will not go beyond 2900 fps as its case capacity, or rather powder or potential gas volume is not enough to keep accelerating the projectile for the full length of that tube. But again the ratio does alter.

These days with all the powders we have from so many manufacturers, most anything can be made to work. Some like efficiency, some like pure velocity. The only real thing that should be considered is what happens to the throat and how quickly it is washed away. There are a number of cartridges that we can call overbore that wash away throats in record time no matter what powder you choose to use. They to a one work best in long tubes because to net the best velocities you need the slower powders which in turn perform best when confined for a longer period of time to build pressure to accelerate the bullet over a greater length of barrel. The trade off in most cases is more grain weight of powder, longer duration of flame front which is not good for throats and more heat generated throughout the barrel. Not all slow powders are as savage on throats or have higher flame temps. H1000 or 2217 is one that has a relatively low flame temp. But being as slow as it is, the flame duration is longer so the end result MAY be the same as that of a powder with a hotter flame temp.

Which ever way you go, there has to be some trade off. There is no way a hyper velocity can be achieved without a loss in some other area.

Tony Z.

PS.
There is something that very few even know about and even fewer consider when making up these hyper velocity rifles. There is a reason that the likes of the 222, 6PPC, 6BR, 30BR and other similar cartridges deliver such outstanding accuracy. They have a muzzle gas exit pressure of about or less than 4000 PSI. A 300 Win Mag in a 24 or 26 inch tube will deliver in excess of 7000 PSI at the muzzle. This gas pressure and volume has an adverse effect on the base of a bullet that has gone though the barrel and has experienced some form of in bore yaw, or as i renamed it, in bore swagging. This leaves the bullet base or pressure ring not square to the LOD and gasses at velocity can and will deflect the bullet tail and set it off line ever so slightly and thus opening up the grouping potential. A 300 Win Mag built on a 30 inch tube reduces this pressure back to the magic 4000 PSI or less where the best potential accuracy is realized. Many of these 30 cal or 7 mm rifles in Heavy Gun application for long range shooting are capable of very small groups at all ranges. But if you dock those barrels back a considerable amount they do not and will not produce an aggregate as they once did. Sure you will get occasional good groups, but the agg suffers overall, and in this game group aggs are everything.
A very oversized case, with a very undersized bore, coupled with a large volume of slow burning powder produces high gas velocity that passes the bullet at muzzle exit playing around with accuracy in some very dramatic ways. So there is now another trade off to consider where a short barrel and higher exit pressures can take away the accuracy that a smaller cartridge would gain from. Longer barrel, lower exit pressure, more velocity and better accuracy. If you are after fine accuracy do not build a 17/06 on a short range principal of a short and stiff tube that will deliver the best accuracy. This will fail. If you have to do it on a short tube, use a faster powder to gain reasonable velocity and less exit pressures for better accuracy.

Before you know it, you are back to 17 Rem ballistics or less. Is there a gain in this for the job at hand is the question that needs to be asked? Without doubt, a 17/06 could be built that will deliver high velocities and possibly very good accuracy, but i reckon a 17BR or 17PPC will exceed those velocities over the lifespan of the barrel, and do it in a shorter tube with far less powder gaining far more potential accuracy and a shitload less recoil. The other plus is that there is far more powder availability and subtle burn rate variations within the scope of the PPC and BR case that an optimum will be quickly found. The 06 version is very limited and will alter in characteristics as the barrel ages (throat washes away).