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1917 Eddystone Range Photos
Last edited by Group Therapy; 04-08-2017 at 12:00 PM.
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04-08-2017 11:52 AM
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Seems to shoot about like it should...
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We are actually surprised that is does this well. But after heating up at about 15 rounds there is a lot of drop. Maybe from barrel droop.
Or is the drop on heating also a sign of a worn out barrel?
It is a fun gun to shoot. And a hoot at the range when the young guys show up next to us with their AR stuff with all the glass on top. I have helped some of them get dialed in. But they are amazed that an old mil surp can actually hit a target with iron sights. I help broaden their world a bit. We all laugh and have fun and are better for it.
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Originally Posted by
Group Therapy
Or is the drop on heating also a sign of a worn out barrel
Possibly from the barrel opening up a bit and losing some of it's traction. I had a .30 cal rifle once that climbed off the target when it warmed up...straight up.
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Advisory Panel
Originally Posted by
Group Therapy
Or is the drop on heating also a sign of a worn out barrel?
Hmmm? Plausibility check?
Coefficient of thermal expansion of steel is about 12 millionths per degree C at human environment temperatures.
So taking a 0.30 barrel out of the freezer at 0 C and firing it so rapidly that it heats up to boiling point - 100 C - will increase the bore by 12 x 100 x 0.3 millionths of an inch.
Or about 0.36 of a thou.
More plausible would be from 10 C on a cold day up to 50 C (when you can't hold it any more).
About 0.12 of a thou.
If that makes the projectile so loose that there is a noticeable loss of muzzle velocity, then the barrel might indeed be marginal, i.e. very worn.
Not worn-out - it's not a bench-rest system! Worn-out is when the rifle is useless for the intended purpose. The 100 yd group seems OK to me.
Just shoot slowly (1 min between shots) and regularly, and see if the grouping then becomes tighter.
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Originally Posted by
Patrick Chadwick
Hmmm? Plausibility check? ...
More plausible would be from 10 C on a cold day up to 50 C (when you can't hold it any more).
About 0.12 of a thou.
If that makes the projectile so loose that there is a noticeable loss of muzzle velocity, then the barrel might indeed be marginal, i.e. very worn.
Not worn-out - it's not a bench-rest system! Worn-out is when the rifle is useless for the intended purpose. The 100 yd group seems OK to me.
Just shoot slowly (1 min between shots) and regularly, and see if the grouping then becomes tighter.
Thanks. We will keep at it. Awe shucks. More range time. Thanks for the details on what might be going on. Certainly this old rifle has its limitations. But it is fun figuring them out.
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... and try different ammo. The Prvi /PPU is not exactly bench-rest material. If the bore is worn, you can bet that the throat is as well. Seating the bullets a trifle further out, and/or using longer bullets (i.e. 168gns) can help to compensate for this by proving better bullet guidance in the transition from the case neck through to the full rifling.
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Thank You to Patrick Chadwick For This Useful Post:
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Contributing Member
Nice rifle!
I'll get myself one sooner or later.
The groups seem ok to me.
I have a similar issue on my SMLE. It tends to drop straight down as soon as it heats up well.
If I shoot with some patience, it stays where it is supposed to be.
Someone suggested that there might be something not 100% ok with the bedding.
Maybe.....
Until now, I shoot it and wait a bit to let it cool down.
She shoots well and I relax in the meantime.
34a cp., btg. Susa, 3° rgt. Alpini
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Good to hear from someone about this. I will be back in Montana shooting it in September and will try the "patient" method! Thanks for the advice everyone.
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Originally Posted by
Group Therapy
Good to hear from someone about this. I will be back in Montana shooting it in September and will try the "patient" method! Thanks for the advice everyone.
GT,
Thinking about the rifling and bore size, you could do yourself some invasive research by 'slugging' the bore with a 00SG ball. Tap it through the barrel from chamber to muzzle then measure the diameter of the grooves and lands. This tells you the real diameter of the bore, and allows you to be a little more careful in bullet selection. Being a .303 shooter (as well as having 2 lovely Eddystone M1917s) I'm used to crap barrel condition. With these older rifles, it pays to stick with flat base projectiles. Leave the boat tails for the newer, younger whipper snappers. The grand old dames like a little help getting their seal right, and a flat base helps a lot with a slower burning powder. Just consider the whole system and where the energy is going and how it gets there.
Had an interesting discussion with a 'learned' colleague at the range a few weeks ago. We were trying to work out why some rifles climb when heating up and others fall. The hypothesis presented was: as a cantilever, the barrel droops a little when heated, hence lowers POI. I'm still thinking through this one. Pat Chadwick has chimed in with some good first year mechanics of materials to help us appreciate the thermal expansion science and he's on the money there when considering the bore.
Enjoy the plains when it gets a little cooler!
Trying to save Service history, one rifle at a time...
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