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Thread: Polishing forcing cone?

  1. #1
    Boolit Master yondering's Avatar
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    Polishing forcing cone?

    Talk to me about polishing forcing cones for slug and buckshot loads. I've seen some comments here and there about improved performance from this, but not a lot of detail.
    How do you do it, what tools are used, how far do you go, etc.

    This would be for Mossberg 500 barrels. I have a bunch of smooth bore barrels and another rifled bore on the way.

  2. #2
    Boolit Master
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    Forcing Cone Reamer,its in front of the chamber, you need to remove it then polish,with a small brake cylinder hone. do the hole chamber, go light on the chamber heavy one forcing cone.When your done it should look smooth from the chamber into the barrel. But most new shotgun forcing cones are removed at the factory. (Steel shot) I dont think rifled Barrels ever hade one,(kick like a mule) Some old smooth bores do (mule).You can buy one from brownells If you got 4 or 5 barrels to do it maybe cheaper to buy one if not a gunsmith... ken

  3. #3
    Boolit Master yondering's Avatar
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    Ajay, thanks for posting the pictures, but I can't get to them. Your links are abbreviated and don't work. FYI, since you're using photobucket, you can make the pictures show up in your posts instead of as a link. When you hold your mouse over the picture title (on the Photobucket website), a drop down menu appears. Click on the code next to "IMG", copy it, and paste it here in your post. This will make it show up as a picture.

    Can you post them again please?
    Thanks.

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    Sorry I tried but failed. It is working here in my post.
    http://www.shotgunworld.com/bbs/view...f=118&t=201503
    Hope it helps
    Ajay Madan
    www.PreciousVideoMemories.Com

  5. #5
    Boolit Master yondering's Avatar
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    Thanks Ajay. How do you keep this brake hone just on the forcing cone, without getting into the rifling or the chamber? It looks like the stones on your hone are longer than my forcing cone; so the stones would ride with the rear edge in the chamber. The sandpaper on a dowel is familiar, I may just go with that.



    FYI, on the image posting thing, just copy the part circled below in red, then paste that into your post. That's all you have to do.

  6. #6
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    Good morning Yondering thanks for the tip. The forcing cones should be at least 1 inch or longer for a smoother launch. Just measure your barrel with a wooden dowel and put a marker dot fron where the chamber ends. Start from that point on to 1inch or 1.1/2 inch and put a foam strip of the same width as the sand paper to create a even outward pressure around the circumference of the barrel.
    Hope this helps.
    Ajay Madan
    www.PreciousVideoMemories.Com

  7. #7
    Boolit Master



    Cactus Farmer's Avatar
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    I do forcing cone reaming and polishing on a regular basis. I have all but 10 gauge and would add that if I even had a call for it.
    That said, Buy the reamer,get a "T" handle socket wrench and the socket to fit the end of the reamer.An extension of 6" or so is helpful. Brake hones are use able but I use special "dowel" like fixtures to polish the machine marks out and follow up with a "Flex-e-hone" until I like the shine. Use the special oil to lube the "flex-e-hone". Regular dark cutting oil for the reamer. This will take a couple hours to get a really shiny cone. An air drill to spin the polishers is a great help.
    I get $85.00 a hole for a premium polished cone,less if they just want a fair job and I don't think the extra polishing does any real good. For my personal guns I just ream and do a polish job enough to rid the cone of most of the machine marks.
    Most folks just want the reduced recoil and the uniform patterns are free. A reaming job will improve your patterns and it will seem if the gun shoots tighter patterns. I think it just includes the few errant pellets that are at the perimeter of your pattern and in doing so makes the gun "shoot farther" than before. I don't think much was ever killed with those odd random edge pellets anyway. YMMV
    Any of you have any ideas on why the recoil seems to be so much less with a long forcing cone? i have a DB Rossi hammer gun with 20" barrels (imp & mod) that will kill crows at 60+ yards every time. DRT dead! I've hunted ducks with it and amazed the other shooters with the long range power of the short barrels.
    Lewis AKA Wright Brothers Gunsmiths

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  8. #8
    Boolit Master
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    I Removed 100s of forcing cones when steel shot came about. Shot (steel or lead) Hits the forcing cone Upsetting the shot.( More recoil) steel like banging two hammers,this makes blown patters. lead makes dents in shot making bigger materns = shorter range

  9. #9
    Boolit Master



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    Quote Originally Posted by Kskybroom View Post
    I Removed 100s of forcing cones when steel shot came about. Shot (steel or lead) Hits the forcing cone Upsetting the shot.( More recoil) steel like banging two hammers,this makes blown patters. lead makes dents in shot making bigger patterns = shorter range
    Kskybroom, just what I thought, bent/dented pellets don't fly straight. The improvement in patterns can be amazing. I had my old(now gone to the range in the sky) talked me into it to lessen recoil, I was skeptical but figured it wouldn't hurt any thing so I did it. Then had to open up the chokes for shooting skeet. Prior to the choke mods I missed or turned them into powder!

    Larger shot seems to shoot better,ie, the change in pattern density is more pronounced with larger shot sizes. I just like it and all my personal guns get a FC job first thing. Even my new little 28 ga. It shoots like a 12. dove this year were just as dead with less shot and recoil on my recent ortho surgery
    Lewis AKA Wright Brothers Gunsmiths

    "Illegitimus non carborundum"

    Political Correctness: A doctrine fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous media, which holds forth the proposition that it is entirely possible to pick up a t*rd by the clean end!

  10. #10
    Boolit Master yondering's Avatar
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    Thanks for the tips.

    Quote Originally Posted by VdoMemorie View Post
    The forcing cones should be at least 1 inch or longer for a smoother launch.
    Sounds like what I need to do for most of my barrels then. Is this true for rifled barrels too? I read somewhere on shotgunworld that rifled barrels should have a short forcing cone, but have no idea of that poster's level of experience.

    Cactus Farmer, are you using the flex hones and special oil from Brownells? I looked at those last night, boy they sure are proud of them. ~$65 for the hone, $13 for 1/2 pint of oil, plus shipping! Is there a better place to get this stuff? Will a fine ball hone from the auto parts store work or are they all too coarse?

    Thanks for the suggestions. I started looking into this thinking it was a relatively cheap improvement for my slug shooting, not so sure now.

  11. #11
    Boolit Master
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    Yondering... A short forcing cone in a slug barrel will Force the slug or swag it into the barrel. Making it bounce back end forth in the barrel.This makes big groups When you pull the trigger the slug will set back in the hull at that point you what the slug to leave the barrel with no upset. Same with shot leave the hull hit choke no upset.. a long focring cone is what your after. Polishing makes it prudy,,,,, Cactus Farmer & Yondeing Way back hunted ducks with lead shot an a 10 ga. (hammer time) Then Steel an a 10ga(Booo) cut my range in half. Many days of patterning an reloading Same.. Learned how to reload steel. Cut a polished my Barrels my ic tube patterns like a mod, mod like a full. This is very hard on my dog.......

  12. #12
    Boolit Master yondering's Avatar
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    Kskybroom, thanks for the reply. This all makes sense for a smoothbore. What about a rifled bore, for use specifically with the Lyman 525 "sabot" slug?

    It seems that a long forcing cone would reduce chances of cutting the wad petals, which is good, but would also act as a long freebore in rifles, with increased opportunity for the wad petals to strip on the rifling once it finally engages.

    I have ordered a long forcing cone reamer to use on my smoothbore barrels, but not sure if I should use it on the rifled barrel, or just polish the forcing cone on that one?

  13. #13
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    Lengthening the forcing cone on a shotgun barrel can improve pattern density and make the load shoot softer. I have a weatherby overunder that had super short forcing cones like they used to use on the old fiber wad shotgun shells. I would bet that the cones were not much over 1/4" and the patterns and kick reflected this. I sent the barrel off and had them legthen the cones to the 1 - 1/2" length and it was a new gun! Patterns were much improved and the kick was reduce noticably. I was so pleased that I sent my Browning A-5 in to have the longer cones reamed also. The A-5 was at about 3/4" long from the factory and the new longer cone did not give the same improvement as the Weatherby did. Was it worth the trouble and cost for the Browning? I don't know as I did not pattern it before the work was done, but I am sure that it did not hurt the performance. The only concern I have is that if you use a wad that does not have a generous over powder skirt it may not do a good job of sealing the powder gases behind the shot cup. Powder gases blowing by the over powder section of the plastic wad may make it to the shot cup and agravate the pattern. Good luck and let us know the before and after results of your forcing cone activities.
    Mtgrs737
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  14. #14
    Boolit Master
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    Yondering.. Got looking at my slug barrels. Thay have about 1 1/4 to 1 1/2 in of forcing cone. (rifled) Give a shot barrel a try. Go at it slow keep the chips to a min.(keeps the cutter cutting smooth) I use synthetic moter oil. (cheap i run it in moms car first) pull out the cone to 1 1/4 to 1 1/2 get the feel of the cutter.. I think i would shoot my slug barrel, Pull 1/2 the forcing out shoot repeat until i found the sweet spot. Be careful on the last turns of the cutter to get a nice cut where the rifling is. Good luck and let us know the results..Ken

  15. #15
    Boolit Master yondering's Avatar
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    OK, thanks for the comments, all.

    I have a forcing cone reamer on order, just waiting for it to get here...

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BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
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