I have a Marlin 1894 CS chambered for 38/357 with factory sights. Whenever I shoot, the first 50 or so rounds end up as fairly tight groupings. As I continue to shoot, the groupings get larger and larger. After about 100 rounds, their all over the place. Could this be caused by the barrel overheating? If not, what else could be causing this?
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Marlin lever-action accuracy problem
- Thread starter cwalker3
- Start date
Bill Mitchell
Staff Alumnus
If the CS has micro-groove rifling,and you're shooting lead bullets,then you're going to get substantial leading that would lead to a loss of accuracy. Cleaning the gun regularly while shooting would help,but going to jacketed bullets would be a better solution.
Bill
Bill
If the problem is not fouling, it is most likely barrel heating. That type of rifle was made primarily as a hunting rifle, where only a few shots are ever fired at one time.
You can test this by repeating the firing without the magazine tube, loading the rifle as a single shot and resting the receiver, not the barrel, on sandbags. If it keeps its accuracy, the problem is not fouling.
On that rifle (and the Winchester as well) the barrel is usually pretty tightly bound to the magazine tube. When the barrel heats, it tries to expand lengthwise. If it can't, then it warps enough to cause inaccuracy. (Remember the cuts in the stock of Mauser military rifles to allow the stepped barrel to expand without contacting the stock?)
A good gunsmith can relieve the binding at the proper places without having the rifle rattle.
Jim
You can test this by repeating the firing without the magazine tube, loading the rifle as a single shot and resting the receiver, not the barrel, on sandbags. If it keeps its accuracy, the problem is not fouling.
On that rifle (and the Winchester as well) the barrel is usually pretty tightly bound to the magazine tube. When the barrel heats, it tries to expand lengthwise. If it can't, then it warps enough to cause inaccuracy. (Remember the cuts in the stock of Mauser military rifles to allow the stepped barrel to expand without contacting the stock?)
A good gunsmith can relieve the binding at the proper places without having the rifle rattle.
Jim
Hey cwalker3 - I have a Marlin 336 in .30-30 and have the same problem. What I discovered is that the barrel grooves attract lead like there's no tomorrow. After only 10-15 shots, the accuracy goes to hell. Once cleaned, I'm back in the park. Try just shooting FMJ and compare your groupings - it really helped me.
Good luck.
Good luck.
Noban. Try sizing your bullets to .310 inch diameter, and heat treating them. Then lube them with a .311 die. That is what I did with my 336, until I sold it. 2 to 2.5 inch groups at 100 yards and little or no leading. Velocity duplicated factory loads.
For that fellow with the .357, try sizing to .002 inch over groove diameter. The bullets should be as hard an alloy as you can get. Heat treated wheel weight metal works good.
Works for me.
Paul B.
For that fellow with the .357, try sizing to .002 inch over groove diameter. The bullets should be as hard an alloy as you can get. Heat treated wheel weight metal works good.
Works for me.
Paul B.