Cantilever question

DRT300 · December 15, 2010, 10:55 PM

I bought a new factory slug barrel with a cantilever scope mount for my 870. I shot several slugs out of it and it seemed to like buckhammers the best but they were still alittle bigger group than I like. I noticed when I was putting the gun up the scope will flex the cantilever but it seems to always go back to its original postion. I was just wondering if this could be why my groups are so big. Maybe the gun isn't holding zero. Should I be able to sight this gun in and remove the barrel, put it back on and the gun still be zeroed?

zippy13 · December 15, 2010, 11:40 PM

Greetings DRT300 and welcome aboard.

Theoretically, the cantilever scope mount should be the best way to go with a shotgun with a removable barrel. The logic being, if the scope is mounted to the receiver, there will be some movement between the barrel and the receiver. And, it assumes the mount is well engineered.

We just had a forum posting by a member with the same comments as yours: His cantilever mount isn't preforming up to his expectations and it doesn't hold zero. Simple mechanics dictate that a cantilevered mount will be subject to more deflection than a double supported mount. To reduce deflection you could apply two basic engineering solutions: First use the lightest scope and rings possible and, second, locate the scope as far forward as possible. These will both reduce theoretical deflection (less loading = less deflection), but possibly not to your satisfaction. Have you contacted Remington to discuss your problem?

Also, your problems may be due to the mounts not being tight. Did you use any non-slip between the scope and rings? Your scope might be doing a slow creep in the mounts.

DRT300 · December 16, 2010, 12:37 AM

I have contacted Remington and am awaiting there reply. I have the scope as far back as it will go right now, because I have no neck and short arms. I might consider a scout style scope all the way forward, that could help. Everything seems tight. I only use this gun for a quota hunt 1 time a year. I think I will mess with it after all the hunting seasons go out here in Kentucky and see if I can figure something out.

94bluerat · December 16, 2010, 07:13 AM

DRT300,

We have been shooting slug guns for 20+ yrs and have seen many different versions of performance. As Z13 mentioned, ensure your scope is fully secured. These things create a lot of force and can mess up a scope. Also make sure the mag tube cap is tightened all the way.
The Buckhammer is a big hunk of lead w/ a large frontal area that will be affected by wind more than a sabot style slug. Remington claims 3 inch at 100yrds, that is likely done with a 24" table mounted test barrel w/ no human contact. Try the Rem copper solids or the Fed barnes expanders, I have had good groups with both of those. Currently I am using the Win supreme partition gold, but I have heard rumors that they may be replaced.
Look at the Tar-Hunt slug gun web site. They used to have some really good info on sighting in slug guns. They focused mostly on lightfields, but the info applies across the board.
Lastly, when doing your range time don't just rest the fore end on the bags or rest. Hold it with your hand as you would in the field, and then place your hand on the support. Big slow projectiles will move the position of the gun before they leave the barrel and that can effect shot placement.

Good luck, shoot lots!

Rembrandt · December 16, 2010, 07:02 PM

One simple fix to eliminate cantilever deflection is to drill and tap a threaded hole (10/32 thread) through the cantilever rail directly above the receiver. Next install a small plastic tipped set screw that will make contact on the receiver....no more deflection.

Jimbow1965 · December 19, 2010, 06:48 PM

94Blue,
The buckhammers in 2 3/4 WILL shoot 3" groups at 100 yards all day long !
I shoot them from a Marlin 512 Slugmaster and they will do it easily.
I even shoot them from my 870 smooth bore and at 50 yrds they are 3" as well. (I got the targets to prove it.)( and I am going to trade in both guns because they knock the crap outa me)
And they aren't really a big chunk of lead...they are actually "T" shaped with a stud that goes back into the traveling...I'm not sure its a sabot...more like a stabilizer...But 1 1/4 oz. I like how they shoot but don't yet know how they will react to a deer....Just my FYI

zippy13 · December 19, 2010, 07:14 PM

Jimbow1965,
Isn't the Remington Buckhammer a plumbata, or impact discarding sabot? The plastic stabilizer acts to significantly shift the center of drag well behind the center of mass, thus improving accuracy.

DRT300 · December 22, 2010, 11:48 AM

According to Tar Hunts website I was going about zeroing all wrong. The gun always shot close at 50 but got wild at 100. Everyday I shot it the wind was blowing but I didn't think it would have that big of an effect on the poi. I'm still going to try the copper solids, or some slug that is more available at my local walmart or sporting goods store.

zippy13 · December 22, 2010, 01:33 PM

Think about it: with it's plastic stabilizer, a Remington Buckhammer is much like a shuttlecock -- have you ever played badminton in the wind?

DRT300 · December 22, 2010, 04:29 PM

Never thought about it that way. I guess your right. The copper solids will probably be my next choice.

DRT300 · January 4, 2011, 04:40 PM

Wonder if a 20ga. would shoot more consistant? Smaller bullet, less drag, etc.????

pabuckslayer08 · January 4, 2011, 05:01 PM

I only shoot 20ga sabots. Own 2 of them and am planning on a 3rd. For slug hunting you dont need 12ga. Ballistics show like 1 more inch of drop and basically no KE drop at 100 yards. However Ive found the 20 to be more accurate and easier to shoot. So why not go 20ga

DRT300 · January 4, 2011, 07:10 PM

The 20ga. drops 1" more at 100, but still retains KE? You shoot 2 3/4" slugs or 3" out of your 20?

December 15, 2010, 10:55 PM	#1
DRT300 Member Join Date: December 15, 2010 Posts: 34	Cantilever question I bought a new factory slug barrel with a cantilever scope mount for my 870. I shot several slugs out of it and it seemed to like buckhammers the best but they were still alittle bigger group than I like. I noticed when I was putting the gun up the scope will flex the cantilever but it seems to always go back to its original postion. I was just wondering if this could be why my groups are so big. Maybe the gun isn't holding zero. Should I be able to sight this gun in and remove the barrel, put it back on and the gun still be zeroed?

December 15, 2010, 11:40 PM	#2
zippy13 Senior Member Join Date: August 23, 2008 Location: SoCal Posts: 6,442	Greetings DRT300 and welcome aboard. Theoretically, the cantilever scope mount should be the best way to go with a shotgun with a removable barrel. The logic being, if the scope is mounted to the receiver, there will be some movement between the barrel and the receiver. And, it assumes the mount is well engineered. We just had a forum posting by a member with the same comments as yours: His cantilever mount isn't preforming up to his expectations and it doesn't hold zero. Simple mechanics dictate that a cantilevered mount will be subject to more deflection than a double supported mount. To reduce deflection you could apply two basic engineering solutions: First use the lightest scope and rings possible and, second, locate the scope as far forward as possible. These will both reduce theoretical deflection (less loading = less deflection), but possibly not to your satisfaction. Have you contacted Remington to discuss your problem? Also, your problems may be due to the mounts not being tight. Did you use any non-slip between the scope and rings? Your scope might be doing a slow creep in the mounts. Last edited by zippy13; December 16, 2010 at 12:01 AM.

December 16, 2010, 07:13 AM	#4
94bluerat Senior Member Join Date: May 30, 2007 Location: South of Canada Posts: 204	DRT300, We have been shooting slug guns for 20+ yrs and have seen many different versions of performance. As Z13 mentioned, ensure your scope is fully secured. These things create a lot of force and can mess up a scope. Also make sure the mag tube cap is tightened all the way. The Buckhammer is a big hunk of lead w/ a large frontal area that will be affected by wind more than a sabot style slug. Remington claims 3 inch at 100yrds, that is likely done with a 24" table mounted test barrel w/ no human contact. Try the Rem copper solids or the Fed barnes expanders, I have had good groups with both of those. Currently I am using the Win supreme partition gold, but I have heard rumors that they may be replaced. Look at the Tar-Hunt slug gun web site. They used to have some really good info on sighting in slug guns. They focused mostly on lightfields, but the info applies across the board. Lastly, when doing your range time don't just rest the fore end on the bags or rest. Hold it with your hand as you would in the field, and then place your hand on the support. Big slow projectiles will move the position of the gun before they leave the barrel and that can effect shot placement. Good luck, shoot lots! __________________ "Got a shotgun, a rifle and a four wheel drive" - HW Jr. Rifleman BSA Eagle Scout

December 19, 2010, 06:48 PM	#6
Jimbow1965 Member Join Date: January 13, 2009 Posts: 30	Buckhammers 94Blue, The buckhammers in 2 3/4 WILL shoot 3" groups at 100 yards all day long ! I shoot them from a Marlin 512 Slugmaster and they will do it easily. I even shoot them from my 870 smooth bore and at 50 yrds they are 3" as well. (I got the targets to prove it.)( and I am going to trade in both guns because they knock the crap outa me) And they aren't really a big chunk of lead...they are actually "T" shaped with a stud that goes back into the traveling...I'm not sure its a sabot...more like a stabilizer...But 1 1/4 oz. I like how they shoot but don't yet know how they will react to a deer....Just my FYI

December 16, 2010, 12:37 AM	#3
DRT300 Member Join Date: December 15, 2010 Posts: 34	I have contacted Remington and am awaiting there reply. I have the scope as far back as it will go right now, because I have no neck and short arms. I might consider a scout style scope all the way forward, that could help. Everything seems tight. I only use this gun for a quota hunt 1 time a year. I think I will mess with it after all the hunting seasons go out here in Kentucky and see if I can figure something out.

December 16, 2010, 07:02 PM	#5
Rembrandt Senior Member Join Date: August 10, 2002 Posts: 2,108	One simple fix to eliminate cantilever deflection is to drill and tap a threaded hole (10/32 thread) through the cantilever rail directly above the receiver. Next install a small plastic tipped set screw that will make contact on the receiver....no more deflection.

December 19, 2010, 07:14 PM	#7
zippy13 Senior Member Join Date: August 23, 2008 Location: SoCal Posts: 6,442	Jimbow1965, Isn't the Remington Buckhammer a plumbata, or impact discarding sabot? The plastic stabilizer acts to significantly shift the center of drag well behind the center of mass, thus improving accuracy.

December 22, 2010, 11:48 AM	#8
DRT300 Member Join Date: December 15, 2010 Posts: 34	According to Tar Hunts website I was going about zeroing all wrong. The gun always shot close at 50 but got wild at 100. Everyday I shot it the wind was blowing but I didn't think it would have that big of an effect on the poi. I'm still going to try the copper solids, or some slug that is more available at my local walmart or sporting goods store.

December 22, 2010, 01:33 PM	#9
zippy13 Senior Member Join Date: August 23, 2008 Location: SoCal Posts: 6,442	Think about it: with it's plastic stabilizer, a Remington Buckhammer is much like a shuttlecock -- have you ever played badminton in the wind?

December 22, 2010, 04:29 PM	#10
DRT300 Member Join Date: December 15, 2010 Posts: 34	Never thought about it that way. I guess your right. The copper solids will probably be my next choice.

January 4, 2011, 04:40 PM	#11
DRT300 Member Join Date: December 15, 2010 Posts: 34	Wonder if a 20ga. would shoot more consistant? Smaller bullet, less drag, etc.????

January 4, 2011, 05:01 PM	#12
pabuckslayer08 Senior Member Join Date: December 18, 2010 Location: South Central Pa Posts: 692	I only shoot 20ga sabots. Own 2 of them and am planning on a 3rd. For slug hunting you dont need 12ga. Ballistics show like 1 more inch of drop and basically no KE drop at 100 yards. However Ive found the 20 to be more accurate and easier to shoot. So why not go 20ga

January 4, 2011, 07:10 PM	#13
DRT300 Member Join Date: December 15, 2010 Posts: 34	The 20ga. drops 1" more at 100, but still retains KE? You shoot 2 3/4" slugs or 3" out of your 20?