What free bore would you recommend for a 300 Norma mag? That is going to be specifically set up to run 245 bergers and 250 atips.
300 Norma free bore?
- Thread starter Deewarr1717
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I would highly consider using a short lead with a long bull rider throat call and talk to Dave Kiff at Pacific tool gauge about it.
Seat a couple of each bullet so the boattail to bearing surface junction is 0.050 in front of the neck shoulder junction and send them to the reamer manufacturer you plan on using.
They will put them on a optical comparator and get you exactly what you want.
They will put them on a optical comparator and get you exactly what you want.
I’d bet JGS or Manson has that number on file somewhere, that’s a very common combination.
I’d stay away from PTG.
I’d stay away from PTG.
That's an improved version 35* shoulder. I'd bet it's spec'd to be able to take 245 bergers seated out properly so that FB should work.
@otnot or @Taylorbok
Can you explain for the uneducated like me where the freebore is in that diagram. TIA
Can you explain for the uneducated like me where the freebore is in that diagram. TIA
I have a 26” 300 PRC shooting a 212 ELD x and I hit around 2850 with H4831 (I believe the 212 has a better bc than the 225 for some reason). My 29” 300 Norma is clocking 3110 fps with a 230 Berger using Retumbo and the accuracy node was 1.5 grains shy of pressure. I like the Norma Mag but it’s a custom barrel and the PRC is a factory Seekins PH2. You’ll have to decide if performance is more important to you than barrel life but I’ve been very happy with the Norma Mag so far. I’ve also found it to be much more accurate than my PRC but it’s not apples to apples in comparison either. Good luck with your decision they’re both rockets.
To answer your ? My chamber is throated 2.863” base to lands.
To answer your ? My chamber is throated 2.863” base to lands.
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.215 is Sammi and CIP spec if I remember right, my last one was like .235 or so, and my current one is .220. Allot of people seem to recommend .250 or so it seems for the longer bullets like the Atips and 245 Hybrid.
I beat this topic to death on my last one and have not seen a huge issue with my .220, and to be honest it was not worth the time I spent on it.
I beat this topic to death on my last one and have not seen a huge issue with my .220, and to be honest it was not worth the time I spent on it.
If you look at the various reamer prints there in 0.060 difference in the freebore and the CIP print has neck taper that is not present in the more benchrest type reamer. The neck diameters are only 0.001 variation but the smaller neck diameter is 0.343
If your running a 0.308 bullet and your necks are 0.015 thick that gives you 0.343 + 0.015 + 0.015 = 0.338 loaded rounds in a 0.343 chamber or 0.005 clearance. That is a safe amount for those not wanting to turn necks.
If you have the tools to turn necks I would not go with more than 0.340 on the neck and stick with the no taper neck.
Mr Wheeler also specified the resize neck diameter at 0.331 which is 0.012 under the chamber dimension. This would give 0.007 neck tension if the loaded rounds were 0.338 diameter.
I don't own or shoot a 300 Norma but given the numbers I suspect 0.336 is what Alex was basing his reamer on?
Foregreens and Henriksen would take 6 months to a year to get you a reamer if they would even do it.
Manson JGS and Pacific Tool average 2 months.
Hugh Henriksen is a hoot to talk with and can answer any questions if you start the conversation out correctly. Call his shop and tell him you need a reamer and your not in any hurry and can wait 4-6 weeks to get it. He will then ask you who sent you his way and just tell him he was recommended on a benchrest forum. You need to say benchrest forum!!! After he quits laughing take copious notes on what he tells you then give that info to someone faster.
If your running a 0.308 bullet and your necks are 0.015 thick that gives you 0.343 + 0.015 + 0.015 = 0.338 loaded rounds in a 0.343 chamber or 0.005 clearance. That is a safe amount for those not wanting to turn necks.
If you have the tools to turn necks I would not go with more than 0.340 on the neck and stick with the no taper neck.
Mr Wheeler also specified the resize neck diameter at 0.331 which is 0.012 under the chamber dimension. This would give 0.007 neck tension if the loaded rounds were 0.338 diameter.
I don't own or shoot a 300 Norma but given the numbers I suspect 0.336 is what Alex was basing his reamer on?
Foregreens and Henriksen would take 6 months to a year to get you a reamer if they would even do it.
Manson JGS and Pacific Tool average 2 months.
Hugh Henriksen is a hoot to talk with and can answer any questions if you start the conversation out correctly. Call his shop and tell him you need a reamer and your not in any hurry and can wait 4-6 weeks to get it. He will then ask you who sent you his way and just tell him he was recommended on a benchrest forum. You need to say benchrest forum!!! After he quits laughing take copious notes on what he tells you then give that info to someone faster.
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