Rem 700 RUM action safe for Lapua/Norma

Dean2

Well-Known Member
Joined
Jul 31, 2010
Messages
999
Location
Alberta
again do as you wish ,
i disagree with you. im not saying i know more than you on this topic, but i do think everyone is pushing it ... and why ? when they make bigger actions

.027 closer is still closer, case angle & larger face, seems to me would add more rearward pressure , not just 65 overall pressure, add an oily chamber to that on a hot day , even though it could still take an extra 10-15 k before breaking , just saying every cut lowers that very real maximum

serious question , what % of that 65 is pushing back and how hard , for each of teh above .. how do you measure that ??
Lord love a duck! Bolt face pressure DECREASES as the surface area of the cartridge head decreases, assuming the same nominal pressure, and vice versa. Pressure from a round being fired exerts pressure equally in all directions, having consideration to the surface area the pressure is being applied on. Thus the sidewalls of a cartridge actually get far more pressure exerted on them than the case head. In the case of a 338 Lapua, the bullet receives somewhat less pressure than the case head becasue the base of the bullet is smaller than the case head and far less than the sides. You disagree with me and have an opinion everyone is pushing it without even the most rudimentary knowledge of ballistics. I am done answering Gun 101 questions, try google and some reading please. Have a great day.
 

DUSTY NOGGIN

Well-Known Member
Joined
Mar 18, 2015
Messages
861
Location
salt lake city
will do, you do the same,

ill go get the correct terminology for the meaning and ask the question again and hopefully you will take the time to understand what im saying before you criticize ,

what you say above, does not address the meaning of what im trying to say
 

Shane Lindsey

Well-Known Member
Joined
Jul 13, 2010
Messages
1,744
Yeh thanks gents:mad: These were clearly answered. I guess I will take the advice and google so I can READ what every other site has to say vs the trusted site I have sought information from for years...

Is it safe to use as a 300 Norma, 300 Norma improved, 338 Lapua?
Is it as easy as a bolt swap, head spacing?
What would need to be done to the receiver rails?
Am I off base?
So a bolt lugs and the action lugs are exactly the same size on the RUM vs Lapua?
Only difference is the feed lips and bolt face?
 

adam32+P

Well-Known Member
Joined
Mar 7, 2021
Messages
288
Location
California
Yeh thanks gents:mad: These were clearly answered. I guess I will take the advice and google so I can READ what every other site has to say vs the trusted site I have sought information from for years...

Is it safe to use as a 300 Norma, 300 Norma improved, 338 Lapua?
Is it as easy as a bolt swap, head spacing?
What would need to be done to the receiver rails?
Am I off base?
So a bolt lugs and the action lugs are exactly the same size on the RUM vs Lapua?
Only difference is the feed lips and bolt face?

Yes.
Yes. Or open the bolt face and add an M16 extractor.
Massaging.
No.
Yes.
Yes.
 

can1010

Well-Known Member
Joined
Feb 27, 2012
Messages
1,281
Yeh thanks gents:mad: These were clearly answered. I guess I will take the advice and google so I can READ what every other site has to say vs the trusted site I have sought information from for years...

Is it safe to use as a 300 Norma, 300 Norma improved, 338 Lapua?
Is it as easy as a bolt swap, head spacing?
What would need to be done to the receiver rails?
Am I off base?
So a bolt lugs and the action lugs are exactly the same size on the RUM vs Lapua?
Only difference is the feed lips and bolt face?
i would suggest you look up the testing Kirby Allen did on those actions with Lapua and Lapua Imp. cases before you make your final decision.

he was experiencing large amounts of lug set back on the actions. after customer complaints he removed the barrels and measured the actions and noticed the lug were set back .010 or more in the action even with moderate loads.

they are saying the cause is bolt thrust not pressure. make your own decision just offering another opinion without the noise
 

MagnumManiac

Well-Known Member
Joined
Feb 25, 2008
Messages
3,946
2 things come to mind doing this conversion.
1) removing metal from behind the bottom lug abutment to lengthen the magazine should be avoided.
2) the bolt face requires bushing, the plunger ejector hole filling and a M16 or Sako style extractor fitted.
So, after removing the factory extractor, the bolt gets a ‘ring’ sweated in place to fill the void. Then machined to fit the new cartridge rim dimension. I use .590” for Rigby sized cases. You can go .595”.
Then the ejector hole is filled and the bolt face is machined for the new headspace.
Another option is a bolt replacement.
The problem going from a .550” diameter case to a .588” diameter case is that it is almost a given that metal will need to be removed from the feed ramp, this is part of the bottom lug abutment.
If it is not done, it will most likely feed badly.
All of the factory 338 Lapua rifles I have seen had dual ejectors, I do not know why, but Remington felt they required it.
It is NOT what I would do.
As to the lug setback, this IS a very real possibility if the feed ramp is altered or the action is altered behind the abutment.
I went through this dilemma building my 338-416 Rigby Improved.
I shyed away from a Rem 700 action and used a CZ 550 Safari Magnum action instead, it started life as a 416 Rigby anyway.
This is the info you need to mull over, is it a deal breaker? That’s up to you.

Cheers.
 

Wolf76

Well-Known Member
Joined
Jan 5, 2014
Messages
922
Location
Grandville, Michigan
I have an edge on a 700 action. Works great and wouldn't even consider a lapua BF without any increase in performance. This is especially true given you're running a 300 RUM.
 

jrock

Well-Known Member
Joined
Mar 12, 2014
Messages
1,297
Location
Idaho
OP, I haven't seen you mention searching this site for similar posts. There are at least 3 in depth posts over the last 5 to 7 years. If you want to keep the 700 action, its pretty straight forward to get a PT&G one piece bolt with the Lapua face and M16 extractor. The money you spend on modifying a 700 action will make a nice dent in the cost of a custom action.
 

cjuve

Well-Known Member
Joined
Feb 15, 2011
Messages
408
Location
SPRING CREEK, NEVADA
After owning several of the cartridges that you are contemplating there is really no reason to step up to a Norma or Lapua over the RUM unless
you are thinking about improving the Lapua or just like having something different. The RUM is a solid cartridge that has a case capacity that falls right between the standard Lapua and Norma.
 

Chamberman

Well-Known Member
Joined
Mar 23, 2012
Messages
317
Location
Caldwell, Idaho
Our shop has performed this conversion many times, with great success and no issues!

To answer your questions: (repeating what adam32+P stated)
1) yes
2) yes
3) the feed lips will need milled out a few thousanths for clearance
4) no
5) yes
6) yes

The thing I am seeing in this discussion is that folks are suggesting removing material from the feed ramp.
THIS IS COMPLETELY INCORRECT!

In order to compensate for the case length you remove .125" from the REAR of the magazine well in order to fit a Wyatts extended magazine box, Bainey magazine box, or equal. You can watch a Video that Kevin Wyatt produced for installation of his magazine boxes.

These receivers have been used extensively on the factory .338 Lapua Rem. 700 Police models with ZERO issues.

If you want to have this rifle built please PM me.
 
Top