16ga.com Forum Index
Author Message
<  16ga. Ammunition & Reloading  ~  Pressure barrel
onefunzr2
PostPosted: Sat Sep 02, 2006 12:53 pm  Reply with quote
Member
Member


Joined: 16 Jan 2006
Posts: 1008
Location: Sandy Lake, PA

I have decided I'd like to check the pressure of my reloads. Factory loads, too. Chronographs aren't real accurate sensing a shot string vs a single projectile. The trail of BB's confuses the sky screens. So for this kind of testing a strain gage should be just the ticket.

I'm gonna order a 16ga barrel for my H&R 1871\NEF Handi-rifle. They only offer it in full choke. Forty something bucks is a cheap way to get a pressure barrel to glue on a strain gage for my Oehler model 43PBL.

My Rizzini B is choked mod and I\C. And there's no way in hell I'm gonna bugger up the new O\U for a strain gage. I need to chemically strip away any bluing, down to the bare metal.

Will the constriction matter in regards to the pressure seen by the strain gage, which is directly over the chamber?
Back to top
View user's profile Send private message
Foursquare
PostPosted: Sat Sep 02, 2006 1:01 pm  Reply with quote
Member
Member


Joined: 18 Nov 2005
Posts: 398
Location: S Fl

The short answer is no.
What form will your data take. Graph (P/T curve) or digital reading of peak pressure, etc?
You might see a small bump in the P/T curve as the projectile mass enters the choke, but compared to chamber pressure, it's a fart in a whirlwind.

If it really concerns you, or you think it's affecting results, saw off the last 3 inches of barrel and chamfer the new muzzle.

Pete

_________________
" .......you have learned patience and stubbornness and concentration on what you really want at the expense of what is there to shoot. You have learned that man can as easily be debased as ennobled by a sport....."
Back to top
View user's profile Send private message
onefunzr2
PostPosted: Sat Sep 02, 2006 5:26 pm  Reply with quote
Member
Member


Joined: 16 Jan 2006
Posts: 1008
Location: Sandy Lake, PA

Foursquare wrote:
The short answer is no.
What form will your data take. Graph (P/T curve) or digital reading of peak pressure, etc?
Pete


Both. Pressure graph and values for peak, rise and area.
Back to top
View user's profile Send private message
onefunzr2
PostPosted: Sun Oct 15, 2006 6:24 am  Reply with quote
Member
Member


Joined: 16 Jan 2006
Posts: 1008
Location: Sandy Lake, PA

All ready to do testing except for one thing: I need to plug in a value for bullet diameter in inches, described as "this diameter is used to scale the area under the pressure curve." I'll have to call Oehler on this one. For a 30-06 Spfld I plug in .308" For a 22-250 Rem I plug in .224" I'm not sure what number is appropriate in this case.







Edit: It turns out that the term 'bullet diameter' should have stated 'bore diameter.' James Bohls @ Oehler said to just measure the outside of an unfired hull on the plastic. This value isn't used to help determine pressure, but to view the graphed output result.

As soon as the wind stops blowing a gale and the sky lightens, I'll be ready to test some ammo.


Last edited by onefunzr2 on Sun Oct 22, 2006 6:14 am; edited 1 time in total
Back to top
View user's profile Send private message
onefunzr2
PostPosted: Sat Oct 21, 2006 4:00 pm  Reply with quote
Member
Member


Joined: 16 Jan 2006
Posts: 1008
Location: Sandy Lake, PA

First test is factory Rem game load...1200fps rated.
Second test is factory Win game load...2 1\2 dr. eq. rated.
Third test is my duplication load for first test...1220fps rated.

FYI, Oehler cautions that the shot clump\wad going over skyscreens read somewhat low compared to inductance sensor.

http://i3.photobucket.com/albums/y57/onefunzr2/16%20guage%20ammo%20tests/PS0003.jpg
http://i3.photobucket.com/albums/y57/onefunzr2/16%20guage%20ammo%20tests/PS0004.jpg
http://i3.photobucket.com/albums/y57/onefunzr2/16%20guage%20ammo%20tests/PS0005.jpg
Back to top
View user's profile Send private message
offhand35
PostPosted: Sun Oct 22, 2006 4:50 pm  Reply with quote
Member
Member


Joined: 04 Feb 2005
Posts: 191
Location: Western Connecticut

hello, onefunzr2!
I'm very interested in your pressure setup. I can't see how your pressure data is interpreted to yield PSI or LUP [or CUP for that matter]

Can you help with that?

Thanks!

_________________
.....SQUIRREL, the OTHER dark meat.....
Back to top
View user's profile Send private message
onefunzr2
PostPosted: Mon Oct 23, 2006 9:12 am  Reply with quote
Member
Member


Joined: 16 Jan 2006
Posts: 1008
Location: Sandy Lake, PA

Units of measure under columns PEAK and AREA are in PSI(M43), not absolute.
RISE is in microseconds.

The presure values seem low so I am waiting for an explanation from Oehler. As I have indicated, the reload pressure as listed by Hodgdon is 9,900psi. My "average" results were 6,860psi(M43). The only difference in the recipe is my substiution of the R-16 wad for the AA16. That should not make that big of a difference.

I might have not done something correctly as this is my first go with a scattergun. All the values for my rifles are right in the ballpark.

I'll update once Oehler responds.
Back to top
View user's profile Send private message
Display posts from previous:   
All times are GMT - 7 Hours

View next topic
View previous topic
Page 1 of 1
16ga.com Forum Index  ~  16ga. Ammunition & Reloading

Post new topic   Reply to topic


 
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum




Powered by phpBB and NoseBleed v1.09