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Thread: Magnum Research .454 showing signs of high pressure

  1. #1

    Default Magnum Research .454 showing signs of high pressure

    So here is the deal. I have a Magnum Research .454 that has had a bisley hammer and Reeder gun fighter grip frame added to it. In addition, the barrel has been shortened to 4 5/8. To make a long story short, I am just now learning the virtues of big bullet low velocity. In the past, I have primarily shot the hornady 240 GR XTP/MAG factory loaded ammunition out of it. I realize it isn't the optimal "bear round" but I got a slew of them for dirt cheap and the gun shoots them well so I have stuck with them. Now, my question is why would this revolver being showins signs of high pressure with this load?https://www.hornady.com/shop/?page=b...oduct_sku=9148
    I sent the gun back to Gary Reeder who did the custom work and had him check the cylinder and frame for major issues. He checked it on the lathe and said it is in good condition still but I need to knock off the high pressure loads. Are these rounds considered high pressure?

    The signs that I am seeing on the revolver that indicate high pressure are that the cylinder is expanding enough to come into contact with the frame while shooting. One can visibly see where the cylinder has come into contact with the frame. In addition, Gary said that the "silver" lines running perpendicular along the top and bottom inside the frame indicate high pressure. The funny thing is that I haven't really had "sticky" extraction. The only other issue is that the little v spring in for the loading gate has jumped out of alignment more than once causing the gun to lock up. Gary sent me out a new spring from Ruger that is supposed to take care of that issue and so far it has.

    The revovler is from the old DM line that Magnum research first started out with. They are supposed to be pretty much identical to the early freedom arms and Ruger blackhawk frames. Anyways, anyone got a clue as to what is going on here?

  2. #2
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    Those loads look as hot as a .460! You must really be expanding the cylinder.
    I don't know much about the early Magnum Research guns but I have two of the newer ones and have no problems. Most accurate revolvers I have ever shot.
    Never depend on sticky brass to indicate pressures, you can go WAY past safe and never get a stuck case. I have worked to a sticky case once in a while testing loads or when a powder had pressure excursions, (Dropped those powders FAST.) but know of overloads that would turn you white, in Rugers, that showed no pressure signs. ( How about 8 gr too much 296?)
    I would call both Hornady and Magnum Research. Something is wrong. I don't think the ammo is right.

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    That load looks on par to me. I show a 240 grain JHP, 31 grains of AA number 9, at 1916 fps and energy at 1955. Pressure and velocity is not the same thing, you can get high pressure and low velocities with a fast powder. The 454 Casull is a high pressure round to start with so it can be easy to get excessive pressure from a poor choice of powder. The 454 is not as far behind the 460 S&W Mag in performance as case length would have you think.

    Now the question is are these home loads or factory ammo? If it is factory ammo you should be good to go, however since this is an older gun I would have it magnafluxed. Since you donít know what was done to it before you got it.
    Andy

  4. #4

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    The gun was actually new when I bought it as it had been on a small dealers shelf for the better part of a decade. Needless to say I got a smokin deal on it. These are factory loads. Appreciate the ideas so far.

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    Default Loads are OK

    Quote Originally Posted by futurerancher View Post
    The gun was actually new when I bought it as it had been on a small dealers shelf for the better part of a decade. Needless to say I got a smokin deal on it. These are factory loads. Appreciate the ideas so far.
    Those loads are right there where top end 454 Casull loads should be. Of course, those statistics were produced with THEIR gun. Have you been able to chronograph the loads out of YOUR gun?

    I am just speculating here, but if you have a "sticky" or high-friction barrel (or just slightly oversized bullets) you could be getting higher than normal pressures and lower velocities. Polishing the bore might improve things.

    With Casull brass and rifle primers as strong as they are, I would not expect to find the usual overpressure signs (flattened primers, sticky extraction, etc), so, the other pressure signs Gary Reeder saw concern me. I am having trouble picturing the "silver lines". Where are they and what are they rnning perpendicular to?

    You say the cylinder is contacting the frame. At the point where this contact is taking place, what is the clearance when the gun is at rest?

    Do you or a friend(s) have another 454 or a 460 from which these same cartridges could be shot for comparison purposes?

    You've got me curious now.

    Lost Sheep

  6. #6

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    okay for those that are curious here are some pictures of cylinder to frame contact.


  7. #7

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    Here are some pictures of the top and bottom strap as well as the cylinder. The contact lines on the cylinder are all in the same spot but not as pronounced as the one pictured. The last picture is one of the revolver for reference.









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    Default What am I missing?

    So, the cylinder is making hard contact with the BOTTOM of the frame opening. With the rub mark on the cylinder where it is (between the chambers and OPPOSITE the chamber being fired), it can't be chamber expansion? When the gun is fired, the place where the cylinder is being marked is at the 6 o'clock position. So, I still wonder at the point where this contact is taking place, what is the clearance when the gun is at rest? Is the base pin a tight fit, or can the cylinder move up and down at bit?

    I have to bow to Gary Reeder's superior gunsmithing skill, knowledge and knowledge of this gun in particular (since he not only has examined it but is also the one who built it). I am completely at a loss for right now.

    I know I am missing something, but I don't know what it is.

    Lost Sheep

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    Don't make sense to me why it would contact down there. The top strap looks fine in the pic, is there something on the top strap that we canít see in the pic? I am guessing you donít have a set of feeler gages so use cut up printer paper as a gage if you don't have a feeler gage set. How many sheets of paper will fit between the cylinder and top/bottom straps?

    I also don't see any stress signs at all, but to show up in a photo stress would be very bad. The marks on the cylinder I see could be from contact when removing or installing it in the frame, or even just from the gun being sat down on a hard surface. The tooling marks go around the cylinder so it's easy to see a blemish running at a 90 to them. It sure does look to be a good match to the marks in the lower frame.

    I would call Gary on the phone and ask him what he meant by "knock off the high pressure loads" What loads is he saying you should be using in it.

    Andy

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    Now that you show pictures of marks on the BOTTOM, I am at a loss unless the cylinder pin is allowing downward movement.
    Maybe there is a high spot in the frame casting too. A combination of the two can force the cylinder down into contact under recoil.
    I don't see anything on the top strap.
    Check how the pin fits the cylinder and back of the frame, you might cure it with a new pin and draw filing the frame bottom with a fine mill file, then polishing it. That sure looks like recoil not high pressure damage.

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    I'm following this thread with great curiousity. After seeing the pictures I went to my gun safe to look at my .454 SRH. The clearance between my cylinder and frame is substantial (admittedly a different design), and if my cylinder was to contact the frame during firing I can't imagine being able to hold the thing as it went bang...and I have pushed the handloading limits pretty far with this pistol and cartridge.

    If your pistol hadn't already been examined by a competent gunsmith, I'd be thinking that the clearance was off, cylinder lock-up failure or misalignment of some sort. However, this problem is out of my range of experience. As I said, I'm following this with interest to learn something from others.

  12. #12

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    When I originally talked to Gary about this he explained that the cylinder upon firing high pressure loads expands and looks like an Egg which in turn causes the cylinder to contact the frame. Good call on the printer paper as most of my goods are in a storage unit right now. I can fit all of one piece of cut printer paper in between the cylinder and the bottom of the frame. I can fit six in between the cylinder and top strap. Does anybody have a BFR or freedom arms to compare that to? As far as "cylinder slop" the BFR is no Freedom arms and there is just a touch of movement even when the hammer is back. However, I would call it cylindrical movement and not actual slop if that makes sense as it just a slight movement of rotation not up down or back and forth movement. Hopefully big Murph will get wind of this thread and have a look.

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    ...it's "Professor Murphy". He's earned an honorary doctorate from us.

  14. #14

    Default paper thin

    If you can only slide one paper thickness, which is about .004", between the cylinder and the bottom of the frame window, I think you just don't have enough clearance between the two and any play at all could cause the mentioned condition. Also, you might mike or have the cylinder miked to see if there is any dimensional discrepancy in the cylinder itself. I'm not saying theis is not caused by high pressure, but then wouldn't there be more then one mark on the cylinder for each chamber?

  15. #15

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    The cylinder was checked and it is still in spec. Those contact lines are present for all five cylinders. The one I took the picture of was the most pronounced and showed up the best after the shot. The other five chambers so to speak have the exact same mark and profile. Just for the record I consider this a magnum research issue and not a Gary Reeder issue as all he did was add the grip frame and cut the barrel. Everything is stock. I am going to link this thread to Gary Reeder's forum where quite a few big bore aficionados frequent. To be frank, when someone like Reeder tells you the pistol has pressure signs it is cause for concern as the guy knows true big bore's that make the .454 look like a .38 special.

    Here is the link to that thread. Look for "issues with revolver" by Brian. http://disc.yourwebapps.com/Indices/183178.html or http://disc.yourwebapps.com/discussi...0Custom%20Guns

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    Default Try checking the true on the cylinder pin

    I went to Gary Reeder's web site and read Jim Taylor's post wherein he said:
    Cylinder Movement
    Sat Jan 10, 2009 21:04

    Bob Baker explained to me one time that when a revolver fires, looking a the cylinder from the side, the front wants to raise up, the rear of the cylinder wants to go downward.

    Basic laws of motion apparently. Since the chamber that fires is higher than the "pivot point" or whatever the technical name is, and the thrust is out the front of the chamber.

    He said they so stressed an FA 454 that the front of the cylinder was flattend to some extent by hitting the top of the frame on the front and the rear of the cylinder was flattend to some extent on the rear of the frame .. where your gun is marked.

    They went so far as to sheer the cylinder pin if I remember correctly, and had to drive the cylinder out of the gun with a leather mallet. The FA frame held.

    Gary understands this and saw the marks for what they were.
    So, what do you find when you pull the cylinder pin and roll it across a known flat surface (window glass, table top or kitchen counter, etc)?

    Is the pin straight? Does it have pressure marks? When you insert it into the cylinder (both out of the gun) is there much clearance? When you insert the pin into the frame (without the cylinder) is there much movement? Can you rotate the pin in the frame without binding (a sign that the pin is not straight or is out of round)?

    Looking forward to the solution. I sure hope one is forthcoming.

    Lost Sheep

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    Now it adds up! Lots of room on top to let the front tip up but only .0045" or so under the back so this is where it contacts as it recoils inside the frame.

    If it were mine I would clearance the lower strap about .005" in the center contact aira, but I would not advise that you do it yourself. The pin is the week point that needs checked as Lost Sheep said. I wonder if there is room to install a larger pin in it

    Donít forget to ask him about the "knock off the high pressure loads" comment. Is he saying to shoot mostly 45LC, or just no hot loader 454ís? I think itís mostly just a cosmetic issue, but itís always better safe than sorry.

    Andy

  18. #18

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    Gary was pretty clear about everything being okay right now with the revolver but said it would be wise to start from scratch with handloads and build up from there while carefully watching for signs of pressure. I haven't handloaded for it yet as I had been shooting those Hornady rounds that I bought for about half what it would cost to reload. That may change now. The pin seems to fit correctly and does not seem out of round to my eye after playing with it a bit. I think the next stage will be to send it in to Magnum Research. Not real excited about shooting .454's out of it until I am 100% confident in it again. I haven't swaged the barrel yet but do you all think there is any chance I've got a tight (.451) bore on it?

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    Default Revolver firing dynamics

    This issue is one that would be fun to take a calculator and some basic engineering and try to solve this interesting problem.

    The expansion of the cylinder shouldn't be too bad although it is an irregular shape. We could probably calculate on the basis of a cylinder as a worse case.

    We know the approx. pressure and diam. of the bore so the backward force on the front of the cylinder is easy to figure.

    The frame will tend to stretch on the top since it is in tension from the forces generated on the barrel and the recoil plate. This would tend to make the frame opening a trapazoid with the larger opening on the top.

    I'm playing with this since I'm not sure I buy the cylinder "tipping' idea. My S&W Xframes don't have much of a cylinder pin in the rear at all; if there was much "tipping" it would shear the small ejector rod extension off; at a minimum I would see contact between the racket and the frame - it is not there. In addition the barrel would show more gas leakage at the top than at the bottom - I haven't see any signs of that happening on any of the many revolvers that I've looked at. Instead I think the pressure on the cylinder is straight back with the force being pressed against the recoil plate by the case. If the cylinder was "tipping" there would be an oblongated wear on the recoil plate - I've never seen that on any gun either. Take out a well used revolver and look at the recoil plate where the 5 or 6 empty or fired case contact it and leave wear marks and you can see my point.

    Could the cylinder simply be expanding until it hits the top of the frame and then be forced downward until it contacts the frame on the bottom? This would give marks similar to what we are seeing in the middle and back of the cylinder and frame, these are the thinest part of the cylinder and would be forced downward more while the front or thicker part of the cylinder would see less expansion and thus less contact. The wear contact points would be similar to the "tipping" theory but from a totally different cause.

    Take a close look at your S&Ws and tell me if I'm missing something.
    Living the urban lifestyle so I can pay my way and for my family's needs, and support my country. And you?
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    I Have a BFR in 500JRH caliber. I cut up a piece of copy paper and could get only three (3) pieces between the cylinder and the top strap and three pieces between the cylinder and the bottom of the frame and both were a very tight fit but went through. Four (4) pieces were impossible in both instances. The cylinder has no movement and is as solid as a rock. As far as quality and workmanship goes, I think BFR is just as good as or better than most on the market today and that includes FA. I tend to go along with bfrshooters comments.

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