Misfire help

[revbc]

Seems my new sb1 357mag has more than its share of misfires.  It is reamed to maxie, and I was careful not to cut the seat for the cartidge rim.  Could a new rifle come with a weak hammer spring?  I think I remember reading that this spring can cause misfires.  Any ideas or help?

Bobby

[trotterlg]

It probably could, but I bet it came from the factory with the rim cut too deep.  If you look at SAAMI case specs you will see that the maximum rim thickness is quite a lot more than what the cartridges have in real like.  Example is a 32-20 chamber I just cut, spec is .065 rim, but what you will find are .060 rims, so if you cut a rim to spec plus a couple of thou to allow for a little dirt you will end up with .007 headspace on most cartridges you fire, and .007 is too much.  I would measure what you really have with the ammo you are shooting.  Larry

[quickdtoo]

I had the too deep rim cut problem with my SS 45-70 Ultra Hunter, I modified the extractor so it would hold the case against the breech instead of being too far into the chamber with too much headspace which solved the problem. You can return it to H&R and they'll replace the barrel, or you can thin the post part of the extractor so it's thin enough to hold the rim against the breech without touching the breech first, then put a dab of epoxy on the front side of the extractor post after cleaning it good.  After curing, file it so the extractor holds the case to zero headspace. Worst cast scenario, you buy a new extractor for it and have H&R fix it right.

Tim

[revbc]

The best I can measure is about .008 from the cart to the barrel face.  Looks like to much to me.

[brennemanj83]

Would H&R replace barrel if he has reamed it to 357 Maxi????Just curious to see how they would handle that.

[quickdtoo]

Oops, forgot about that, I don't think so, but Gardner did replace a barrel that someone had an aftermarket brake installed, I don't remember the details, but they did replace it. Dunno if Remington would and in this case, they could easily say whomever rechambered it cut it bad and probably would charge for a replacement barrel, so sending it in isn't really an option. 

Tim

[trotterlg]

You could try the old TC trick and, using a small center punch, punch the rim cut in the barre all around.  The dimples will take out at least .005 inches which could be enough to do the trick.  I also measured a .357 ejector, mine has .065 inches from the rim to the breach, I would take off .006 and let it hold it nice and tight to the breach face.  Larry

[revbc]

I was wondering if they would check the barrel to see if it had been altered.  It shoots so good I really don't want to send it back

What about this................If I took some JB weld or other hi pressure epoxy (isn't there something better than JB weld), coated a new brass, chamber, and barrel face with release agent, carefully added the epoxy to the rim cut, pressed the new brass in until flush with barrel face, let it setup.

Do you think it would work?  Seems there shouldn't be much pressure in that area.  Whatcha think?

Bobby

[quickdtoo]

That may work, I made that suggestion to Richard I think when he thought he cut his 45-120 rim to deep, but I like Larry's idea better, you can always do the epoxy if it isn't enough. You don't need it built up all the way around just in a few spots to hold it against the breech face. My fix worked excellent and the extractor post is the only thing holding the case.

Tim

[trotterlg]

You should probably also measure how far the primer is recessed below the rim on the ammo you are shooting, all of these thing add up and can give just the results you are getting.  I have a spare .357 ejector I will mill down until it has a rim thickness of .059, that should fix the problem, if it works just send me your old ejector.  Larry

[kevinsmith5]

I had several misfires in my BC when I first started shooting at longer ranges because I was focusing so hard on not jerking the trigger that I wasn't pulling it back far enough to keep the transfer bar out of the hammers path.  Once I learned to carry the trigger all the way back when the hammer strated to fall this problem disappeared.  Could this be the OP's problem rahter than a problem with the mechanics of the rifle?

[quickdtoo]

An ejector won't work in an extractor underlug unless you add a short spring or an extension of some sort to the works, it's quite a bit shorter than an extractor, the retainer pin is also in a different location, so it either needs to be relocated or the ejector thinned to match the extractor profile.

Tim

Ejector on top

[dpe.ahoy]

Larry, you are just to darn nice!  I think you are one of the "Handi-angels".  How is the retirement going?  DP

[revbc]

Larry,
I appreciate the help if yours is an extractor.  Mine is one of the new sb1s with extractor.  The best measurement I could come up with is the brass is about .008 below flush with the barrel.  I reloaded about 20 rds and only pressed the primers in just enough to get them out of a lee hand primer.  This helped some......instead of 5 or 6 misfires out of 20 it reduced it to 1 in 20.

Larry, I'll PM you if what you have will work.

Thanks,
Bobby

[trotterlg]

Sorry I didn't get right back, (long story, went Coyote hunting with a cold, there was a lot of snow, hiked in too far and have been sick for a week).  I only have ejectors, but I think it would work to take some off the face of the extractor so it is just the depth of the rims on the ammo you are using and then put a spring at the bottom to push it up and hold the cartridge against the case.  Quick can tell you if this would work, but I don't seen any reason it would not.  I don't know if the extractor barrels have the pin at the end of the lug to keep the spring from falling out, so you may have to put one in.  Larry

[quickdtoo]

The short spring I add to ejectors when I convert them to extractor will work, you end up with a spring backed up extractor, the extractor cam compresses the spring, if the case sticks, it ejects, if it doesn't stick, it just lifts the case out. Spring length and size is critical tho, it must be long enough to push the case out, but be able to compress and become solid in case you get a sticky case. The pic I posted earlier is an ejector underlug converted to an extractor, the ejector claw(top) is shown with a short spring that sits between the extractor cam and the end of the ejector.

You may be able to just shorten the extractor a little, just enough to add a short spring that will hold the case against the breech face as Larry mentioned but the extractor post still needs to be thinned so it doesn't hit the breech face before the case does, otherwise it will allow more headspace, on top of the primer being slightly recessed, you may still get misfires. Older ejector barrels had deep rim cuts too, but the ejector spring held the case against the breech face so it wasn't a problem.

Bobby, if this isn't your cup O'tea, I'd be glad to fix it for ya.

Tim

[revbc]

Gentlemen,

This site and all of you are the greatest....................   Tim, I may take you up on the offer, but first let me give it a go.  I did take off the face of the extractor the amount of difference between the rim cut and the thickness of my brass, about .009.  Didn't put a spring behind it though, so it probably won't hold the case to the breech.  I am I correct?

Bobby

[trotterlg]

You will need a spring of some sort to hold it back.  I have a bunch, some that are a little thinner wire than a regular ejector spring, so they can be compressed shorter without the coils touching.  If you want I will send you a selection, you can cut them down more if you need to.  You will need a pin at the bottom of the extractor channel to keep the spring from falling through however.  Larry

[revbc]

Thanks Larry,

I'll PM you my info.  Do you think the .009 is enough off the face of the extractor?

Bobby

[trotterlg]

I think .009 is probably enough, all I need now is your address.  Larry