Model of 1917 chamber length

Been playing with my Win Model of 1917 trying to get it to shoot better original 10/17 barrel ME one plus throat is about the same the crown is good but the bore is really dirty but appears to be cleaning up. Out of curiosity I tried a un scientific way of measuring the chamber length. I closed the Bolt and slid a 1/4" wooden dowel down the barrel until touched the Bolt face and made a mark then I opened the Bolt slid just a 150gr bullet into the chamber until it made contact with the rifling and then re-inserted the dowel until it touched the bullet and made a mark it measures 3.30" between the marks which seems pretty tight to me. Anyone else tried this

Griff557--

You need a throat erosion gauge to check and see how bad it is. Another quick way is to take an empty .30-06 shell case (NOT LOADED) split the neck on opposite sides. Than gently seat by hand a bullet into the mouth of the split case. Than ease the case with bullet into chamber of your rifle until the action is closed. Very gently open the action and extract the cartridge out the rifle. The rifling in the barrel will push the bullet back into the case until the action locked. That should give you an idea of the length of the leads in the rifling. The cartridge length will be different between bullet designs.

--fjruple

I've checked the throat with a gauge it measures just a bit over 1 what I was trying to do was get an idea of what C.O.A.L to load without pushing the bullet into the rifling

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Originally Posted by Griff557

I've checked the throat with a gauge it measures just a bit over 1 what I was trying to do was get an idea of what C.O.A.L to load without pushing the bullet into the rifling

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Griff557--

By checking the leads with the actual bullets that you are going to use and backing off a faction of an inch will get you the best results for setting up the cartridges that you intent to use in your rifle.

--fjruple

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Originally Posted by Griff557

an idea of what C.O.A.L to load without pushing the bullet into the rifling

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Another seated a bullet in a case and used black marker to see when it touched the commencement of rifling. Just start long and keep pushing it into the case until the marker comes out untouched.

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Originally Posted by browningautorifle

Another seated a bullet in a case and used black marker to see when it touched the commencement of rifling. Just start long and keep pushing it into the case until the marker comes out untouched.

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That's where Iam headed next...I think my theory of measuring the chamber was ok but the execution probably wasn't as accurate as it should've been. Using a Hornady 150gr flat base bullet I only came up with a C.O.A.L of 3.30" I have to believe the chamber is longer than that

So I put magic marker on some Hornady 168 HPBT I had loaded C.O.A.L 3.304" and eased them into the chamber and closed the bolt when I extracted them I could see very light rifling marks on the shoulder of the bullet....answered my own question-I think

SAAMI COL for 30-06 is 3.340 max. If you have to make the round any longer than that for a milsurp you have a seriously worn throat and will never have good accuracy.

Serious bench rest shooters with high end custom barrels play with their cartridge lengths and create rounds that can't be used in any other rifle than the one the round was built for. That's not the way a military rifle works. They are designed to use a round coated in mud so the chambers and the throats are always a little oversized. For that reason some freebore is built into them and you will always get more brass swell and stretch than a commercial chamber. - Bill