Just wondering if this is possible. I have a bighorn long action and would love to be able to get a 300 Norma barrel for it. And just buy another magnum bolt head and have it opened up to Lapua size for the Norma. So is this possible?
Gunsmithing Opening Bighorn Magnum bolt face to Lapua sized?
- Thread starter jda2631
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No, the bolt's are NP3 coated and last I checked Bighorns don't have the safety margin to handle the larger cases.
It won't take a .585 bold face, or it doesn't have the AOL to handle it?...or both?
I'm nowhere near qualified to say if it is or isn't strong enough. But just looking at the saami specifications for 300 wm, 300 Norma, and 338 lapua. 300 win mag has 64k max pressure, 300 Norma and 338 lapua actually have lower specified max pressures. 63k and 60k respectively.
Again, I am not qualified to say the action is or is not capable. Just posted saami cartridge specs. And 300wm is no problem for the action.
That info that I'm passing is from Bighorn. There's already been a few over the years that have wanted to do the same but Bighorn has told them the actions can't safely handle the larger cases. If the manufacturer is saying its a bad idea, I for sure wouldn't do it especially when it involves removing material from the bolt, thus reducing the structural integrity of the whole package and leaving it in a more unsafe condition. Not to mention the coating of the bolt head is going to make it a pita and likely damage tooling in the process.
If you really want to know the in's and out's of why it won't be a good idea, just call Bighorn and they'll be able to explain it more in depth.
Or maybe @BigHorn / ZAI Team can explain here why they don't recommend it.
If you really want to know the in's and out's of why it won't be a good idea, just call Bighorn and they'll be able to explain it more in depth.
Or maybe @BigHorn / ZAI Team can explain here why they don't recommend it.
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The Bighorns are not rated for those cases. Hence why the bolt head doesn't exist, it's not because they forgot or somehow don't know how to make a bolt head and extractor.
I'm the one who did the analysis for Bighorn and said "No bueno" on the idea. The topic was discussed between AJ and myself back when he was the HMFIC in 2012 time frame. We revisited it in 2015 when Zermatt bought the company. It's still no bueno.
The magnum heads aren't made from the same material as the smaller heads for strength reasons.
Long story short, armchair engineering on guns is foolish. Don't do it.
I'm the one who did the analysis for Bighorn and said "No bueno" on the idea. The topic was discussed between AJ and myself back when he was the HMFIC in 2012 time frame. We revisited it in 2015 when Zermatt bought the company. It's still no bueno.
The magnum heads aren't made from the same material as the smaller heads for strength reasons.
Long story short, armchair engineering on guns is foolish. Don't do it.
Also, pressure alone is not a good ruler to measure action strength/suitability. A 338lm at 55ksi surely puts more stress on an action than a 6.5 cm @ 62ksi. To compare two different head diameters on pressure alone is apples to oranges.
Pressure is measured in pounds per square inch.
The Lapua and Norma rounds are larger in diameter, larger area, therefore they load the lugs with a higher pressure vs a 300 WM.
I’ve seen a few 338 edges on Bighorns.
I’ve wanted the same Norma from Bighorn and asked a few years ago and they hinted it may come sometime from a new action. With the Origin project, I’m not holding my breath.
That said, is it a bolt weakness or action body, or a combination of both?
I’m only aware of the ARC Mausingfield that is a normal LA that has a LM bolt head available, and not a bigger size action. Are there more?
I’ve wanted the same Norma from Bighorn and asked a few years ago and they hinted it may come sometime from a new action. With the Origin project, I’m not holding my breath.
That said, is it a bolt weakness or action body, or a combination of both?
I’m only aware of the ARC Mausingfield that is a normal LA that has a LM bolt head available, and not a bigger size action. Are there more?
Pressure is measured in pounds per square inch. You need a certain amount of lug area to handle the pressure. Going from a .700" diameter bolt with 1-1/16 threads to one with a .750" bolt diameter and 1-1/8" threads increases surface area considerably. Increase in surface area is not linear. The formula is (Pi) R squared.
duramaxed:
The Badger M2013 Long action is available in both Magnum and Lapua bolt configuration.
The action itself is the same, the bolt/internals are different.
For all the info about this you would need to give Marty a call.
The Badger M2013 Long action is available in both Magnum and Lapua bolt configuration.
The action itself is the same, the bolt/internals are different.
For all the info about this you would need to give Marty a call.
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