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Topic: having a chamber cut to a dummy round ? (Read 214 times) previous topic - next topic

having a chamber cut to a dummy round ?

I'm getting a barrel made for my 6mm creedmoor and going with a shilen from nss...all they have for the 6 creedmoor is blanks so their going to send a blank back to shilen to cut the chamber .. james  from nss told me to send 3 dummy rounds to shilen and they will cut the chamber to where my dummy rounds will touch the lands... so heres my question... how do I determine oal on the dummy rounds ? do I use book length ? do I seat the bullet I plan on shooting the most to where the bearing surface and boat tail junction are just below the neck and shoulder junction ? the six creedmoor is a known barrel burner so I don't want to make them too long to where I cant chase the lands or they get to long to fit the mag... suggestions would be appreciated...
Grant

Re: having a chamber cut to a dummy round ?

Reply #1
Take the longest bullet you plan on shooting and seat it to have the boat-tail/bearing surface junction just ABOVE the neck/shoulder junction.  I would not get that junction past the neck.

Re: having a chamber cut to a dummy round ?

Reply #2
....do I seat the bullet I plan on shooting the most to where the bearing surface and boat tail junction are just below the neck and shoulder junction ? the six creedmoor is a known barrel burner so I don't want to make them too long to where I cant chase the lands or they get to long to fit the mag... suggestions would be appreciated...

This is where I would be I think without a lot of consideration. Interested to hear what others say. I have -0- 6 Creedmoor experience.
Dave

Re: having a chamber cut to a dummy round ?

Reply #3
Take the longest bullet you plan on shooting and seat it to have the boat-tail/bearing surface junction just ABOVE the neck/shoulder junction.  I would not get that junction past the neck.

Hey Grant. I think Robin just said what we were talking about on the phone last night. From the boattail end the bearing surface should be just ABOVE the neck/shoulder junction of the brass. With that setting when you develop your load, it leaves a little room to seat the bullet a little deeper if you need to jump the ogive 10-40K to the lands.

That’s the advantage of getting the chamber custom reamed - you optimize the chamber throat for the specific bullet you want to shoot.

Re: having a chamber cut to a dummy round ?

Reply #4
That makes a lot of sense Jerry I was just pondering Robin's response when you posted up.
Dave

 

Re: having a chamber cut to a dummy round ?

Reply #5
thanks guys.. robin you had told me that awhile back in a message ... in the message you suggested that I seat it just above that junction or just below it but not on it as that's where the pressure ring is and can cause seating depth to move around a little... again thankful to have a place to go to for answers to questions that are above my pay grade...:)
Grant

Re: having a chamber cut to a dummy round ?

Reply #6
well had 4 different pills and 3 of them were within .006 of each other from base to ogive so took the longest of the 3 and made my 3 dummy rounds seating the boatailand bearing surface junction just above the shoulder and neck junction and got them sent off to shilen today.. the longest of the 4 I have is the 108 gr. eldm and its .045 longer than the others so I will use them after the throat grows some.. the 107 gr. smk is the one I made the dummy rounds with... guess now its a waiting game while shilen cuts the chamber... wasn't a couple hours after talking to james at northland that my new barrel nut and lug along with a action wrench was shipped ...and the barrel blank he had was on its way to shilen... that's the kind of business I like dealing with... no messing around... order it send it...tooo bad its a 8 to 10 week wait on the barrel... if it had been in stock it would have shipped with the rest of my stuff...thumbs up to nss...













Grant

Re: having a chamber cut to a dummy round ?

Reply #7
Patience is supposed to be a virtue. It’s sure not one of the two virtues I can claim. 😄

Grant how do the 110s compare with the 107s?

Re: having a chamber cut to a dummy round ?

Reply #8
On in stock items from James @ NSS they're in my hands the next day!
Dave

Re: having a chamber cut to a dummy round ?

Reply #9
That’s not fair!

Re: having a chamber cut to a dummy round ?

Reply #10
jerry the 110's are actually .004 shorter from base to ogive than the 107 match kings.. the 107 was .667 the 110 was .663 and the 105 berger hybrid was .661 and the 108 eldm is .713.. the 107 is what I have been shooting the most of and they seem to be pretty easy to tune... ranger says the 110s do better in the wind but are harder to tune...I havnt tried them yet but will with the new pipe...
Grant