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 Post subject: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 12:25 pm 
Field Grade

Joined: Mon Jun 25, 2007 3:54 pm
Posts: 44
Has there been any research done on pattern efficiency (or inefficency) when shooting 2-3/4" shells in a 3-1/2" chambered barrel?

I ask because I traded for a shorter barrel, then noticed it wasn't just a 2-3/4" and 3", it was a super mag 3-1/2" barrel. I also ask because I know what happens to accuracy in pistols and rifles when the throat length changes. Lastly, I also ask because I'm not the best game shot and I don't need any more hinderances when the ducks start to fly.




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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 2:56 pm 
Tournament Grade

Joined: Tue Sep 12, 2006 1:40 pm
Posts: 248
Location: On the range, hopefully.
I don't know of any formal research on this issue. However, I have an SBEII which I use mostly for sporting clays and trap using 2 3/4" shells. I have also patterned the gun with 2 3/4" shells on the pattern board, and with 3 1/2" shells with turkey loads. The gun throws excellent patterns with both shell lengths.

Elliott


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 Post subject: Re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 3:14 pm 
Shotgun Expert
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Location: Plainfield, IL
mchang wrote:
Has there been any research done on pattern efficiency (or inefficency) when shooting 2-3/4" shells in a 3-1/2" chambered barrel?


Yes, and it suggests a 10% loss in pattern efficiency. None of it matters when you pattern your own gun.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 6:00 pm 
Diamond Grade

Joined: Mon Dec 17, 2007 9:41 am
Posts: 1551
Oberfell and Thompson who researched pattern efficiency back in the 50's (if i recall correctly) reported an increase in pattern density when firing 2 3/4 inch shells from 3 inch chambers. Again i memory serves the increase was in the region of 3 to 4 per cent. If it is very important to you I can retrieve the book and quote the exact figures.

Now if those results would be obtainable from a 3 1/2 chamber is another story and one poster above quotes research that says no.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 6:02 pm 
Limited Edition

Joined: Wed Dec 06, 2006 6:14 pm
Posts: 314
Wouldn't shooting a short shell in a long chamber be kinda like having lengthened forcing cones? Sorta, kinda?


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 6:05 pm 
Crown Grade

Joined: Tue Jul 03, 2007 7:16 pm
Posts: 4383
2 3/4" shells in a 3" chamber work pretty good. Some of the better target guns are made that way, K80 for one. The extra half inch jump in a 3 1/2" gun might be a bit distruptive.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 6:17 pm 
Gunsmith
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Short shell in a long chamber is the opposite of lengthening the forcing cone. You made the shot have a "speed-up" zone that creates more velocity of the shot against the steep ramp effect of the forcing cone.

A longer gap is against physics when trying to minimize shot deformity. No way anyone (regardless of respected name) will eliminate physics effect. The only way to prove is by testing the very same barrel choke combo, and I have done enough experiments to prove that going from a longer chamber to a shorter chamber is an improvement. Conversely, the opposite must also be true.

I had a long back-n-forth with someone who believed that any difference was non-existent and he tried every way to downplay every aspect that I explained.
See for yourself.

Go to my website, see the "article selection" page link, click to go there, scroll to the bottom of the page to see the link to the first comprehensive discussion.
The other link down there is the one to a later discussion that also has the link to the Browning website page that verifies that shooting a 2-3/4" shell in a 3" chamber has a loss of pattern efficiency, and they even show altitude pattern changes expected. I was discussing the 3-1/2" like here now, and the effect must be more pronounced.

[email protected]

_________________
Gunsmithing website:
http://theshotgunshop.net
Articles on every page.
Article 3 pictures improper or dangerous choke installations, article 1 has explanatory illustrations, and article 2 has info. about bore/forcing cone improvements/limitations.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 7:19 pm 
Presentation Grade

Joined: Tue Jul 03, 2007 8:16 pm
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Location: Washington CH, OHIO
Kirby I've seen many articles that say that there is negligible effect when shooting short rounds in large chambers. I will look up one specifically because it was from a very reputable source.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 7:30 pm 
Crown Grade
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Browning cites a 10% pattern loss when using 2 3/4" shells in a 3" chamber:

http://www.browning.com/faq/detail.asp?ID=102

I would think a 3 1/2" chamber would lead to further losses.

Of course, a loss of pattern density could also be thought of as a wider pattern, so it's always a good idea to pattern your own gun with your own ammo and see if the results are acceptable.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 8:14 pm 
Diamond Grade
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Joined: Sun Nov 11, 2007 6:55 pm
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I think the gap between the end of the hull and the start of the bore would allow the shot column to widen out yes? then as it hit the end of the chamber the lip would peel back or tear up the wad petals. So the shot column is partly or perhaps fully unprotected and being abraded by the bore walls. The extra bit of deformation from the unprotected shot column will add a few fliers into the group resulting in a slightly larger group. Ya think?


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 9:07 pm 
Presentation Grade

Joined: Thu Feb 03, 2005 7:22 pm
Posts: 561
mchang
This has been discussed several times. As someone said already Browning publishes a 10% loss in pattern density with 2 3/4" shells in a 3" chamber. It's probably not an issue for most but you really need to know how your own gun patterns before making a determination.
If you are using a 2 3/4" shell in a 3 1/2" chamber though I could see the dynamics compounding considerably.
The attached article by Randy Wakeman does a good job of explaining the issue.

I noticed that Randy already responded to your thread but he is not the boastful type so I'll point you to his article.

http://www.chuckhawks.com/chamber_length.htm

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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 10:37 pm 
Gunsmith
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Joined: Thu Jan 25, 2007 1:40 am
Posts: 906
Location: St. Louis area
This is the thread where I explain the problem and testing of chamber length (I do get rather comprehensive):

http://www.thehighroad.org/showthread.php?t=246219

Here is the later thread with more vague explanations yea or nay.
The topic was mainly about slugs in long chambers.
http://www.thehighroad.org/showthread.php?t=320928

Here is the enhanced visual that I made to make various aspects clear to see.
This is also part of the article at my website home page. Just scroll down past the photo of my custom chokes to read the complete article.

Image

If you want the article posted, let me know and I'll put the text here, also.

[email protected]

_________________
Gunsmithing website:
http://theshotgunshop.net
Articles on every page.
Article 3 pictures improper or dangerous choke installations, article 1 has explanatory illustrations, and article 2 has info. about bore/forcing cone improvements/limitations.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 11:07 pm 
*Proud to be a*
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Joined: Wed Oct 15, 2003 8:11 pm
Posts: 2771
Location: Houston, Texas
Humm...

I've read the thread, the articles and have to wonder if there is any practical difference in pattern efficency when shooting short shells in a long chamber.

I can only write of my experience with an X2 Wncester which has a 3.5" mag chamber/receiver.

This gun patterns very well with Briley extended chokes and several trap/skeet loads.

It prefers STS LT Target #9 and a Diffusion Choke for skeet distances and dense centers. I shot this gun for a year at skeet and found the chamber length not to be the cause of any missed targts.

Also nearly any quality 7 1/2 shot target shell has pattern density sufficent to break any clay target within 50 yards with the same choke.

While understand the discussion, it would be very difficult to demonstrate any practical difference in this gun.

On the other hand, I have a Browning O/U with long forcing cones-- 2 3/4" chambers and cones long enough to chamber and close the action on an unfired 3.5" shell. I have before and after patterns and can see little difference with 3x1 1/8 oz 8s. The pellet count most likely only varies within the standard deviation expected between shots or strings of shots.

So now tell me, John Milton, how many angels can dance on the head of a pin?

_________________
A strong body makes the mind strong. As to the species of exercise, I advise the gun. This gives moderate exercise to the body & it gives boldness, enterprise, and independence to the mind. Let your gun be your constant companion.
T. Jefferson (1785)


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 Post subject: Re: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Wed Jan 30, 2008 11:23 pm 
Shotgun Expert
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Fish Springs wrote:
This gun patterns very well with Briley extended chokes and several trap/skeet loads.

It prefers STS LT Target #9 and a Diffusion Choke for skeet distances and dense centers. I shot this gun for a year at skeet and found the chamber length not to be the cause of any missed targts.

Also nearly any quality 7 1/2 shot target shell has pattern density sufficent to break any clay target within 50 yards with the same choke.




Part of the problem is definition; I have no idea what "patterning very well" might mean to you. We hear it all the time, or at least I do . . . "patterns great," etc., etc. Great for what? Beyond improvement great? Patterns just fine does not give a basis for comparison.

"Also nearly any quality 7 1/2 shot target shell has pattern density sufficent to break any clay target within 50 yards with the same choke."

I'll have to wish you really good luck with that one; you really need to pattern @ 50 yards and consider the footprint of an edge-on target. The shell alone has no specific pattern density; we rely on the entire system of the shotgun to form it not the least of which is the choke.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Thu Jan 31, 2008 7:52 am 
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Back to Milton and a discussion the number of angels that can dance on the head of a pin....

_________________
A strong body makes the mind strong. As to the species of exercise, I advise the gun. This gives moderate exercise to the body & it gives boldness, enterprise, and independence to the mind. Let your gun be your constant companion.
T. Jefferson (1785)


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Thu Jan 31, 2008 8:23 am 
Diamond Grade

Joined: Fri Feb 27, 2004 4:35 pm
Posts: 1377
Location: Oklahoma City Ok.
You all over analize and think too much. Just pattern your gun and see what works for you.
K.I.S.S.


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 Post subject: Re: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Thu Jan 31, 2008 3:39 pm 
*Proud to be a*
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Ruddyduck wrote:
You all over analize and think too much. Just pattern your gun and see what works for you.
K.I.S.S.


Exactly!

_________________
A strong body makes the mind strong. As to the species of exercise, I advise the gun. This gives moderate exercise to the body & it gives boldness, enterprise, and independence to the mind. Let your gun be your constant companion.
T. Jefferson (1785)


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Thu Jan 31, 2008 6:18 pm 
Limited Edition

Joined: Sun Oct 21, 2007 4:41 pm
Posts: 488
I think your choke will have the final influence over the pattern more so that just 3/4" of extra chamber. i never have a problem i shoot 2 3/4" shells in a 3 1/2" chamber all the time.


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 Post subject: re: Pattern of 2-3/4" shells in a 3-1/2 chamber
PostPosted: Thu Jan 31, 2008 6:26 pm 
Field Grade

Joined: Mon Jun 25, 2007 3:54 pm
Posts: 44
Well, I was going to get around to patterning it as soon as it gets above 10 degrees here in WI., but was curious if there was a known and demonstrable effect I had not heard about, not being a scattergun guy.

Spent the last 20 years getting a decent ranking in Bullseye pistol and getting my Distinguished badge, and now find that I like to shoot things that taste good, hence the grouse, pheasant and duck hunting. And when my boss wanted to trade his 26" Rem 870 barrel for my 28", since I wanted the shorter barrel anyway, and he IS my boss, I did it. Then we both noticed his was a 3-1/2" chamber barrel.

Being overanalytical and somewhat anal compulsive (YES, I'll admit only to "somewhat"), I thought I'd ask the Pros.

So, like all things "gun" the answer is, "It depends. Test your own gun and see what happens."

Thanks, all. It's been interesting reading and e-ing.




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