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Contender Misfires

What Causes Them and What to Do About Them
By: Mike Bellm
 

     The Contender frame is one of the most misunderstood firearms components, but there is no need for the confusion that exists.

     Hammer springs can be weak or broken and firing pins can be broken, but the most common cause of misfires is due to the frame doing what it is supposed to ... DO NOT FIRE IF IT IS NOT LOCKED UP PROPERLY.

     Look at your barrel's locking bolts. That top surface must slide under its mating surface inside the frame in order for the barrel to be locked up and safe to fire.

     Look inside the frame with the barrel off of it. Above and behind the top of the trigger is a little butterfly looking plate hanging there at an angle. This is called the interlock. When the locking bolts engage the frame, they push back on the forward end of the interlock. On the back side of the interlock is a tab that holds the hammer block safety up when the barrel is open, OR, if it is not locked up sufficiently to be safe to fire. The hammer block is the wide, flat bar inside the frame in front of the hammer that slides up and down as the frame is cycled. It is NOT a transfer bar, in case that is what you think it is.

     In order to fire there is a chain of events that have to happen:

     1) The locking bolts must engage the frame far enough to be safe to fire.

     2) The locking bolts must rotate the interlock far enough that it FULLY releases the hammer block so that

     3) the hammer block is FREE to fall out of the way of the hammer when

     4) the striker hits the forward end of the sear, the sear rotates, and at the same time

     5) releases the hammer AND the upper arm of the sear releases the hammer block.

     (Note that the upper arm of the sear holds the hammer block up at all times until the sear is rotated and the hammer block is released along with the hammer. But it is the interlock that also holds the hammer block up if the barrel is not fully locked up... or if there is no barrel on the frame of course. Take some time playing with the frame, follow the sequences, and I think you will soon understand how it works. If you do, you will be one of the very few that do. A big percentage of Contender shooters, dealers, AND "gunsmiths" don't.)

     OK, so the locking bolts must engage the frame and release the hammer block. Fine. So what is happening when it won't fire? This assumes you can cock the hammer in a normal manner. Failure to be able to cock the hammer is another subject.

     Two very simple things prevent the locking bolts from engaging into the frame far enough to release the hammer block safety.

     1) The top surface of the locking bolts is too high. This is just the particular tolerance
 variations in a particular barrel and frame combination. Older vintages of barrels and frames
 may be more prone to this problem, but it happens every day in new, current production as well.
 It happens.

     2) The cartridge case sticks out of the chamber too far due 9 times out of ten to the person resizing cases not understanding how to adjust the size die to bump shoulders back on
 bottleneck cases. In firing, the frame stretches a bit. This stretch lets the case grow in length
 from shoulder to head. If this excess length is not removed, it interferes with the barrel
 closing... it is too long, too big. Make it right and it will work.

     (A third item has been mentioned, and that is a bent extractor, but I assumed that one would
 straighten or replace an extractor that was bent, especially if bent badly enough to interfere with
 closing the barrel.)

     What to do......

     If you close an empty barrel, cock the hammer, pull the trigger, and the hammer block does not drop, the locking bolts are too high and either need to be replaced with undersize locking bolts, which TC does make and sell for this purpose, OR the top surface of the locking bolts must be lowered by proper metal removal. A Diamond EZ Lap is the best tool I have found for this.

     BUT, even if the block does drop with an empty chamber, the end of the tab I referred to on the interlock may not be getting moved out of the way FAR ENOUGH to not rub on the hammer block and impede its fall.

     Therefore...... you should also ink the top of the locking bolts with a felt tip pen, then open and close the barrel several times to get a "signature" in the ink showing how far the locking bolts are sliding under their mating surface in the frame.... called, btw, the locking table. The locking bolts should show the ink marred to a point about 1/32" forward of the "U" notch in the locking bolts.

     If they do not, then either order a set of undersize locking bolts from TC or learn the correct way to dress down the top of the locking bolts.... if you are up to doing it yourself. If you aren't, then contact TC about sending your problem barrel and frame to them check out and repair for you as needed. (Working down the tops of the locking bolts will be addressed in another section on this site as time permits.)

     OK, you have addressed the lockup issue. Everything is fine, but you get misfires, still. Remember the hammer spring. It should be replaced periodically anyway. If it feels even the least bit soft or mushy, definitely replace it. If you are shooting military .223 Rem ammo, it has a harder primer and TC does not warrant the Contender to shoot it. It will when things are right, but normally, it may not. Make sure the firing pins look normal and are not broken. Push them forward through the breech face and examine them.

     This leaves only one thing left. The barrel is not closing all the way.

     Once in awhile a barrel will be too long from the hinge pin back, and the barrel will hit on the breech face before the locking bolts drop down far enough to engage the frame. Not common, but it does happen. You can send it to TC, contact me, or take a few judicious strokes with a file on the end of the barrel to correct this. This is rare, so don't go whacking on your barrel until you are sure this is needed.

     Once in awhile the chamber is not cut deeply enough for factory ammo or new factory cases, rimmed or rimless. Usually TC cuts chambers amply deep. You are most likely to encounter this problem with custom barrels. Cutting the chamber deeper is the cure if it is for a factory round, best done by someone who knows what he is doing with chamber reamers. If it is for a wildcat round, the size die may need to be shortened enough to permit it to push shoulders back farther.

     But.... 9 times out of 10, Failure to Lock Up Is Due to a Loose Nut on the Reloading Press.... the operator. Virtually nowhere I have seen are you being told in the mainstream gunzines or by most of your guru buddies about the fact that "give" in the frame lets cases grow in length when fired. If this extra length of the case is not removed, guess what? The case is too long for the chamber. If it is too long for the chamber, guess what? It has to be crammed in by slamming the barrel shut. And if it is severe enough, even slamming the barrel shut will not push the case into the chamber far enough to allow the barrel to close fully and lock up as it should.... thus due to the No. 1 cause, cases too long, you get misfires. 

     You must bump shoulders back or eventually be faced with misfires and extraction problems due to cases too long for the chamber.

     And by "too long" I am talking about from shoulder to head on bottleneck cases, not the overall case length.

     Bottom line is this.  The Contender is not a Bolt Action.  Nor is it a fixed barrel single shot rifle.  It is a break open design.  It does give when fired, and this "give" lets the cases get too long.

     And..... You CANNOT do an accurate job of adjusting the size die with the barrel on the frame, unless, that is, you take steps that I am not going to cover here.  With the barrel on the frame, anything you do by way of size die adjustment is a blind stab in the dark.  You can make it work, absolutely, but you won't hit that "sweet spot" where it is just right.  

     The best results are normally where the case head sticks out of the chamber about .001" LESS than what the gap between the barrel and frame measures.  I.E.., such that the breech face is not cramming the case forward and up in the chamber when you close the barrel.

     At this point, I refer you to The Experiment Every Contender Shooter Should Perform.  Read it, do it, and you will then understand what happens when a case is fired in a Contender.  Knowing what happens, you will then see one of the most common, most useful cures for misfires.

     And guess what?  Your misfire problems will most likely suddenly go away.  But don't be too surprised if extraction is easier and accuracy is also better.

     (Hint: If a case sticks out of the chamber too far because it is too long from shoulder to head, what is the situation when a bullet is seated out too far?  Same thing, and the same potential problems.)

     (Another Hint: If you continue to fire rounds that are too long and slamming the barrel shut on them is only giving minimal lock up, you stand a strong risk of rounding the locking table in the frame and ruining it.  It may be locked up enough to fire, but the minimal contact surface between the locking bolts and the frame cause accelerated wear on the frame at this point.  When this happens, the next step is the barrel coming unlocked and flying open when fired.)

     I think this is a good time to insert my favorite quote:

     "Most men occasionally stumble over the truth, but pick themselves up and continue as if nothing had happened." Winston Churchill

     Many erroneous ideas exist about sizing cases.  Many times they work fine for years, whether they are well advised or not.  But again, 9 times out of 10 when someone complains of misfires, it is due to not full length sizing cases  and doing it correctly.  If you understand this point and try other methods, you will at least know what to fall back on when misfires do occur.

- Mike Bellm

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This article reprinted with permission of Mike Bellm and Bellmtcs.com
 
Warning: All technical data mentioned, especially handloading and bullet casting, reflect the limited experience of individuals using specific tools, products, equipment and components under specific conditions and circumstances not necessarily reported in the article or on this web site and over which The Los Angeles Silhouette Club (LASC), this web site or the author has no control. The above has no control over the condition of your firearms or your methods, components, tools, techniques or circumstances and disclaims all and any responsibility for any person using any data mentioned. Always consult recognized reloading manuals.