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Saami pressures

Saami pressures
« on: February 13, 2019, 09:12:39 AM »
Saami shows the same pressure for the .270 Win. and the .300 Wea. mag.:
65,000.

If the pressure is the same, why such different actions?  9 vs 6 lug?


Re: Saami pressures
« Reply #1 on: February 13, 2019, 01:28:05 PM »
Good question. I donít necessarily think the number of lugs is a significant factor.

I donít own a Mark V...does Weatherby have bolts with magnum bolt faces in a 6-lug rifle?

It may just be a design standard that Weatherby is going with. They may have just wanted additional design margin.
JK

Re: Saami pressures
« Reply #2 on: February 13, 2019, 03:59:06 PM »
Saami shows the same pressure for the .270 Win. and the .300 Wea. mag.:
65,000.

If the pressure is the same, why such different actions?  9 vs 6 lug?



In the book, Weaherby, The man, The gun, The legend on page 195 there is the a full explanation of the Mark V action. In order to answer your question I would really have to re-type it all. I think you can get it in an Ebook now. It is worth the purchase price. I've learned so much about Roy Weatherby and my rifles and I've put a lot of myths to rest.
Weatherby Rifles:
M5 USA .257
M5 USA 6.5-300
M5 USA 300
M5 German 300
M5 .308 TRR
VG .308
VG 270
Other:
Win M70 30-06
Brn XBolt HC Speed 300 WSM
McMil G30 Dynasty 270 WSM
Ber B-14 HMR 6.5 CM
Mar 1895 SBL 45-70
Win 94 pre 64 30-30
4 AR-15 Match 5.56
2 AR-15 Match Wylde .223
1 AR-10 Match .308

224KING

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Re: Saami pressures
« Reply #3 on: February 13, 2019, 04:44:36 PM »
I rely on my copy to inform myself and answer other's questions,but there are lots and lots of things that are misstated or not even talked about in the book.I'm on the fence about it.If you buy it for info on Roy Weatherby himself,and Weatherby Inc. it's great.If you buy it to rely on the numbers given you will be misinformed in multiple accounts.
« Last Edit: February 13, 2019, 04:49:08 PM by 224KING »
Sorry... Yesterday was the last and final day for any and all complaints whatsoever.

I try to avoid temptation unless I can't resist it.

Everyone has a photographic memory.Some just don't have film.

Re: Saami pressures
« Reply #4 on: February 13, 2019, 04:50:51 PM »
I rely on my copy to inform myself and answer other's questions,but there are lots and lots of things that are misstated or not even talked about in the book.I'm on the fence about it.If you buy it for info on Roy Weatherby himself it's great.If you buy it to rely on the numbers given you will be misinformed in multiple accounts.



This is true, you have corrected me several times and I do appreciate it. I think the info the OP wants is ok though.
Weatherby Rifles:
M5 USA .257
M5 USA 6.5-300
M5 USA 300
M5 German 300
M5 .308 TRR
VG .308
VG 270
Other:
Win M70 30-06
Brn XBolt HC Speed 300 WSM
McMil G30 Dynasty 270 WSM
Ber B-14 HMR 6.5 CM
Mar 1895 SBL 45-70
Win 94 pre 64 30-30
4 AR-15 Match 5.56
2 AR-15 Match Wylde .223
1 AR-10 Match .308

224KING

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Re: Saami pressures
« Reply #5 on: February 13, 2019, 04:53:59 PM »
Yes
Sorry... Yesterday was the last and final day for any and all complaints whatsoever.

I try to avoid temptation unless I can't resist it.

Everyone has a photographic memory.Some just don't have film.

Re: Saami pressures
« Reply #6 on: February 14, 2019, 01:04:57 AM »
Both are rated at 65,000 but the area of the base of a .270, is somewhat less, than the area of the base of a .300 Weatherby.  Area increases significantly as diameter is increases, so the .300 Weatherby has a lot more "volume" of gas pushing against it's base, than the .270, although their pressure ratings are the same.  To make an exaggerated comparison, a road bike bicycle tire holds air at 100 or so PSI, give or take.  A tire on a semi holds air at around 100 PSI.  The tire rubber on a semi truck tire has to be a great deal thicker to contain the same air pressure, as the bicycle tire.  MM

Re: Saami pressures
« Reply #7 on: February 14, 2019, 09:10:00 AM »
Hmmmmm......  100 pounds.

Each truck steer tire is holding up 6,000 pounds at rest.  A bigger footprint than a bike tire for sure.  : )

Granted the .300 has a bigger 'footprint'.  But to me this means that the pressure on every square MM on the bolt face is actually less than that on a smaller headed cartridge under the same pressure.   We can chalk all this up to a 'greater margin of safety', and I'm alright with that.  There are a lot of two lug guns holding back these round shoulder monsters though......

224KING

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Re: Saami pressures
« Reply #8 on: February 14, 2019, 10:35:47 AM »
It's not about what the strength of the Mark V action does on a daily basis.It's what it does under extremely rare occurrences of over burden.That's what matters.
Sorry... Yesterday was the last and final day for any and all complaints whatsoever.

I try to avoid temptation unless I can't resist it.

Everyone has a photographic memory.Some just don't have film.

zonie

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Re: Saami pressures
« Reply #9 on: February 14, 2019, 11:01:42 AM »
I really don't think how many lugs per say has anything to do strength of the weapons action or brass case.  Take for instance Remingtons model 788 with  9 rear locking lugs up to 65 K , so what does that mean ?  absolutely nothing other than the rifle is designed to handle the working pressures of 65,000 psi.  You could take a falling block action or  break action and they still handle 65,000 psi.  I'm not that into why Weatherby designed his actions  the way he did maybe someone on here can enlighten us. 

Re: Saami pressures
« Reply #10 on: February 14, 2019, 02:35:43 PM »
I really don't think how many lugs per say has anything to do strength of the weapons action or brass case.  Take for instance Remingtons model 788 with  9 rear locking lugs up to 65 K , so what does that mean ?  absolutely nothing other than the rifle is designed to handle the working pressures of 65,000 psi.  You could take a falling block action or  break action and they still handle 65,000 psi.  I'm not that into why Weatherby designed his actions  the way he did maybe someone on here can enlighten us.



In short and as I understand it, Roy found that a lot of people were working up really hot loads for his rifles. He wanted an action that would not only handle 200,000 cup but also protect the shooter in case of a catastrophic failure. The bolt needed to be one piece not two piece. It also needed to be vented to allow gases to escape out the side to protect the shooters face. The action also redirects pressure out the bottom and can blow open the floor plate. I think in another thread there is an example regarding an 80+ year old gentleman who survived a case separation unscathed. It destroyed the rifle but no one was hurt. Roy's design has nothing to do with exceeding SAMMI spec's, they remain the same and should not be exceeded.
« Last Edit: February 14, 2019, 02:37:45 PM by HighDesertHunter »
Weatherby Rifles:
M5 USA .257
M5 USA 6.5-300
M5 USA 300
M5 German 300
M5 .308 TRR
VG .308
VG 270
Other:
Win M70 30-06
Brn XBolt HC Speed 300 WSM
McMil G30 Dynasty 270 WSM
Ber B-14 HMR 6.5 CM
Mar 1895 SBL 45-70
Win 94 pre 64 30-30
4 AR-15 Match 5.56
2 AR-15 Match Wylde .223
1 AR-10 Match .308

Grouchy

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Re: Saami pressures
« Reply #11 on: February 14, 2019, 03:15:39 PM »
Hmmmmm......  100 pounds.

Each truck steer tire is holding up 6,000 pounds at rest.  A bigger footprint than a bike tire for sure.  : )

Granted the .300 has a bigger 'footprint'.  But to me this means that the pressure on every square MM on the bolt face is actually less than that on a smaller headed cartridge under the same pressure.   We can chalk all this up to a 'greater margin of safety', and I'm alright with that.  There are a lot of two lug guns holding back these round shoulder monsters though......
  Hey, I understand and will offer to take those Mark V's in Weatherby Mags off your hands for 10 cents on the dollar! LOL! That  is Pounds Per Square Inch , right?

Re: Saami pressures
« Reply #12 on: February 14, 2019, 04:44:10 PM »
Just about all modern bolt action rifles have the same overpressure protection features. I have seen a small ring Mauser action chambered in a .257 Weatherby that was loaded hot enough that the bolt was seized.

I have seen some Remington 700 actions survive some events that I thought no rifle could possibly survive. The shooters all walked away...
JK