August 12, 2014, 07:51 AM | #1 |
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Causes of hard bolt lift?
Or in the case causes of hard lever operation.
Are there any other causes than high pressure that would cause a lever action rifle to be very hard to open? Background, I have put a fair number around 100 rounds through this rifle using trailboss and H4227 with no problems what so ever. I obtaine a load from a third party, published, but not by a major reloading, powder or bullet manufacturer. I ran the load through quickload and it looked fine, around 18000psi (as far as I know the action and this cartridge has been proofed to 64000psi, so a huge margin for error???? I wanted to reduce the load in order to achieve a desired velocity, reduce recoil and minimise or prevent leading. So I tested some loads at load and -1 through to - 5.5 (5 of each) all seemed to work fine, all hit an 8" target area at 100 yards. There were no signs of pressure, all primers looked normal and no extraction issues! I took the same rifle back to the range two days later, with 20 of the most promising load loaded. The first two shoots missed the target and were around a foot wide of the same, extraction and primers were normal. The third shot missed by the same margin, I couldn't open the lever at first, I waited 2-3 minutes and then with a hell of a lot of effort it opened. The case looked normal, the primer looked normal. I fed the empty case back into the rifle it slipped in fine and then extracted fine? I then tried it again, same thing, again, on the forth chambering inj went in fine, but took a lot of effort to extract (I assume this was the same orientation as upon firing). What happened? When I say effort I mean a serious amount (though no tools were required). I can only assume a pressure spike? The powder in question is fast, double base and extruded (N110) The cartridge a 375W. The projectile 379-250 LEE. Cases winchester 3rd firing. It may not be the powder to blame as there is one other factor, I slugged my bore at .376" and have been using the bullets unsized at .379" (I have order a .377" die but the post is letting me down on this item). Whilst .003" over bore is a touch too much this doesn't explain the 125ish rounds success before number 126. Was it a pressure spike due to a reduction in the powder or did the bullet stick for a 1/2 ms before moving on? I have been reloading cast for a while now, but until recently I had always exclusively taken my reloading data from Lyman or Hodgdon (ADI) as I was exclusively using their powders (I am in no way blaming VV powders). I did however step in to uncharted territory and in doing so may have invited unecessary risk! Is this a phenomenon likely to repeat itsels, am I trying to push too big a bullet with to little powder? Have I been stupid? |
August 12, 2014, 08:18 AM | #2 |
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Only thing I can give you is reduced loads can be dangerous. If you are using quick burning pistol powder to propel a cast bullet in a large rifle case, insert the powder and then put a fluff of dacron pillow stuffing on top of the powder before seating the bullet. I used that in my 458 and 375 Magnum safari rifles for cast bullet loads. The fluffy dacron burns up to a puff of smoke.
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August 12, 2014, 02:16 PM | #3 |
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Are you full length resizing? Lever action has limited primary extraction power, so neck sizing is not advisable. Extraction will get harder progressively.
N110 is a good powder. I use it for m1 carbine. I tried under load up to 10% below recommended minimum, and it has been alright. -TL |
August 15, 2014, 05:20 PM | #4 | |
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Quote:
I think, I reduced the load too much about 23% The source was not my usual, Lyman or powder manufacture data, but a published third party load. I rechecked Lyman and a powder manufacturers data and I think I will give one of these loads a go H4198 18 grains (approx 1390fps), H4895 25 grains (approx 1360fps) and H322 24 grains (approx 1490fps) are the powders for reduced loads. The first two listed by Lyman and the last by the manufacturer! |
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August 15, 2014, 06:02 PM | #5 |
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too many possibibilities
Did you at least run a brush through that rifle to remove the lint from a week sitting in a closet? and you should be full sizeing that brass. I would make those loads again but full size and run a chamber brush and bore snake through the rifle and try again.
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August 15, 2014, 10:12 PM | #6 |
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Those other powders are slower than n110. They probably won't do any better for reduced loads.
It is likely that your partial length resizing has caused the difficulty to extract. It is for bolt guns. Lever action should be considered same as semi loaders. Full length resizing to have 0.003" to 0.005" head clearance. -TL |
August 15, 2014, 11:32 PM | #7 |
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TL, the .375 Win case head spaces on its rim; it is a straight walled rimmed case. That is not sized by any die. Head clearance is fixed by subtracting rim thickness from chamber headspace. Case and chamber diagrams are on page 3 in:
http://www.saami.org/PubResources/CC...ifle.pdf#page1 Click on it. |
August 16, 2014, 01:25 AM | #8 |
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Thanks, Bart. I kept thinking bottle necked cartridge. But when it comes to hard extraction, the same principles apply. I would full length resize to bring the external dimensions back within limits. I think the die is resizing the case, but just not bumping the shoulder. The casing is not straight straight-wall. It has slight taper in it.
-TL |
August 16, 2014, 06:46 AM | #9 |
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TL, by straight wall, I meant it doesn't have a shoulder on it. And they've been called "straight walled" cases for decades.
I don't know of any straight walled (shoulderless) centerfire cartridge that doesn't have a slight taper of its body diameters. http://ohiooutdoorjournal.com/2014/0...r-season-2014/ |
August 17, 2014, 09:36 AM | #10 |
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win94oz, I do not know if you have posted this question on other forums, it looks familiar. I believe reduced loads are cute. I have no interest even when all I 'gotta' do is use pistol powder when forming wildcat cases.
A foreign company did some research and decided in their research a reduced load can render a rifle scrap, not every time but there is always the potential. So I do not use reduced loads, all the other American shooters are convinced if it does not happen every time it does not happen. They are the ones that blame double charges for their rifles laying in a heap like the Deacons Master piece, nothing before, then suddenly and all at once it was rendered scrap. F. Guffey |
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