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Question on steel ammo balls

Posted: Tue Feb 23, 2010 7:49 pm
by Gun Freak
I found these steel balls on Fastenal and I was wondering if these would be good for half inch schedule 40 pvp pipe or if they would be too big for the pipe or if I should get the 15/32 size. My gun is Coaxial so there is no breech load, and it needs to be able to slide all the way down the barrel smoothly.

Thanks
~Gun Freak

Posted: Tue Feb 23, 2010 7:55 pm
by Gippeto
Measure your bloody barrel id. Are you REALLY that lazy??

Posted: Tue Feb 23, 2010 7:59 pm
by Gun Freak
Oh yes... that might help :D How the crap do I measure it though?! I don't really have a precise measuring ustensil :?

Posted: Tue Feb 23, 2010 8:10 pm
by iknowmy3tables
please search before you post,

you may have heard that there is no such thing as a dumb question, but on a forum that is not the case,
obviously the 1/2" means the balls are 1/2" in diameter, you have just used a ruler and measured the ID (inner diameter), there are small variations in pipe ID so we can't tell you exactly what the ID on your pvc is, but generally just about all 1/2" sch40 pvc has an ID larger than 1/2". in the future if you want to know the approximate dimensions of common pvc pipe just google it or measure it your self
Gun Freak wrote:Oh yes... that might help :D How the crap do I measure it though?! I don't really have a precise measuring ustensil :?
do you have a ruler? then you have a measuring tool, your lazy no excuse,

Posted: Tue Feb 23, 2010 8:44 pm
by Gun Freak
Gun Freak wrote:precise measuring ustensil
Rulers are for large measurments in inches and centimeters. Not hundreths of inches.

Posted: Tue Feb 23, 2010 8:51 pm
by MrCrowley
Gun Freak wrote:
Gun Freak wrote:precise measuring ustensil
Rulers are for large measurments in inches and centimeters. Not hundreths of inches.
What about millimeters? You don't need hundreds of an inch on a ruler to find a good fitting projectile.
I'm not sure how close 1/2" ball bearings really are to 1/2", but don't worry about hundreds of an inch. Oh and btw, there are multiple charts and tables on this website and the internet with exact inside diameters of PVC pipe. Have fun looking for them.

Posted: Tue Feb 23, 2010 8:52 pm
by roboman
Gun Freak wrote:
Gun Freak wrote:precise measuring ustensil
Rulers are for large measurments in inches and centimeters. Not hundreths of inches.
Besides, if you wanted to get a somewhat precise measurement, you could just go to Harbor Freight and get a $10 digital calliper. I have one. Frankly, it's a piece of crap, but it works for measurements down to .010-ish

Posted: Tue Feb 23, 2010 8:56 pm
by Gun Freak
I used the chart on this sit and found it to be slightly over .6 inches ID, but those vary with brands.

Posted: Tue Feb 23, 2010 8:58 pm
by MrCrowley
Gun Freak wrote:I used the chart on this sit and found it to be slightly over .6 inches ID, but those vary with brands.
Then I question why you asked us in the first place. There's no way we can tell you the I.D of your barrel down to hundreds of an inch.

Posted: Tue Feb 23, 2010 8:59 pm
by Gun Freak
I didn't ask what the exact measurment of my barrel was :)

Posted: Tue Feb 23, 2010 9:01 pm
by MrCrowley
Then use a ruler and find out a "rough" diameter... :roll:

Posted: Tue Feb 23, 2010 9:08 pm
by Gun Freak
You don't understand what I'm saying. I asked if a half inch steel ball would typically fit inside half inch sch 40 pvc pipe. Not what the ID of my pipe is.

Posted: Tue Feb 23, 2010 9:11 pm
by MrCrowley
NSF-PW or DWV?
If you know the ID of your barrel, then you can answer the question yourself. On the assumption that most, if not all, PVC pipes have larger diameters than their nominal diameters, and the 1/2" bearing is indeed half inch, it will fit in your barrel.

Posted: Tue Feb 23, 2010 9:14 pm
by Gun Freak
It is NSF-PW. Yes, I figured it would fit, because the barrel is a tenth of an inch wider than the diameter of the ball.

Posted: Tue Feb 23, 2010 11:02 pm
by roboman
The ID of 1/2" Sch. 40 PVC is slightly under 5/8", probably close to .615. So, yes, it would fit, albeit loosely.

.1" is quite a bit of slop, when you're talking about ammunition fit. That comes out to be .050 on each side, leading to blowby and power loss. If you really want to use that size, I suggest wrapping them in a sabot (even a simple paper towel would help).

The best fit you could get, using fractional sizes, would be 19/32". 5/8" is slightly too big, and would require you to bore out your barrel. If you have a lathe, this is a viable option, however, I'm assuming you don't, since if you did, this wouldn't be a problem.