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Posted By: Philbert Decoding Ithaca Choke Designations - 05/22/10 08:03 PM
I recall seeing somewhere what the differnt Ithaca choke designations mean; i.e. 2, 4 etc. but cannot find it again.

Can anyone point me to where I might find the "decoder ring"?
Posted By: Drew Hause Re: Decoding Ithaca Choke Designations - 05/22/10 08:20 PM
4=Full
3=IM
2=M
1=IC
0=C

Sorry-don't have the actual dimensions but this is what Hunter Arms used. The 16g bore was .650 into the early 30s however.
http://www.lcsmith.org/faq/chokedim.html
Posted By: Researcher Re: Decoding Ithaca Choke Designations - 05/22/10 09:10 PM
On a few early Ithacas when, they first started marking choke,
they marked a fraction 4/4, 3/4, 2/4, 1/4, 0/4 but it didn't take them long to figure the numerator is all they needed. From about 1934 or 5 on S=skeet choke.
Posted By: Philbert Re: Decoding Ithaca Choke Designations - 05/22/10 10:36 PM
Drew and Researcher,

Thank you. I just picked up a 1917 Flues 12 ga. marked 2 and 4 which should mean mod and full. The gun appears unmolested. Both bores measure at .717. Right choke measures .712 and left .695 so more like skeet 1 and mod. I found an Ithaca-source chart in Shotguns by Keith that says full is .693 and mod .711 very close to what I measured but the chart is based on a.729 bore. Any thoughts?
Posted By: Drew Hause Re: Decoding Ithaca Choke Designations - 05/22/10 11:01 PM
Here's a 1919 Flues 12g at .736
http://www.champlinarms.com/Default.aspx...&GunID=1874
Posted By: 2-piper Re: Decoding Ithaca Choke Designations - 05/23/10 03:11 AM
The British proof charts have showed 16ga @ .662" since way back about the mid 1800's when they worked out the tables. 17ga is .649" so a .650" bore would have been proofed as a 17 in England. Of course here in the US gunmakers were at liberty to make a bore size whatever they felt like without the necessity of it being marked for size. Early L C Smith specs do show the 16ga as having a .650" bore, but all other sizes are standard per the British charts.
My H grade Lefever bearing a 1907 patent date currently has bores of .669" in both bbls. I cannot of course attest they are original, but both bbls have 4+ inches of choke with .035" constriction (.634"). I really don't think it started life with bores .019" smaller than current. It is a rather high condition gun, not showing abuse or even very heavy use.
Posted By: Philbert Re: Decoding Ithaca Choke Designations - 05/23/10 04:04 AM
The thing that surpised me is that the bores measure .717 for a 12Ga. It's almost as if they were bored incorrectly (since the chokes compare favorably with published data from Ithaca).
Posted By: 775 Re: Decoding Ithaca Choke Designations - 05/24/10 04:08 AM
I had an NID 10ga(mag, 500xxx) in my hands that was stamped with 4 on both flats...which I thought normal..but it also had a "PLUS" sign after the "4", it was an outline, not a line script like "+" but more like a Red Cross symbol.

Not seen that mentiond before?

Best,
Mark
Posted By: Researcher Re: Decoding Ithaca Choke Designations - 05/24/10 05:27 AM
That cross or plus sign is the mark of Charles August, meaning he proofed the gun.
Posted By: 775 Re: Decoding Ithaca Choke Designations - 05/24/10 09:09 PM
Thank you Reasercher.
Posted By: MJBilbo Re: Decoding Ithaca Choke Designations - 05/25/10 08:37 PM
That cross symbol meant that you will have to visit the local Urgent Care for a shoulder x-ray after firing that 10 ga a few times.
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