Guys,

I have a Rem 700 SPS in 300WM. I have always wanted a 300 Wthby. Can I just run a reamer into the barreled action and clean up the Win. Mag chamber to the Weatherby round. It just seems too simple???

Thanks for the advice in advance.

Elk Country

Be sure the magazine and the ejection port will handle loaded rounds. The Weatherby is a long magnum round- same as the 300 H&H and 375 H&H. The 300 WM is a standard magnum round.
Not sure about the chamber, may need to ask your gunsmith or download the Saami specs to check it out.

Bob

[quote=Sheister]Be sure the magazine and the ejection port will handle loaded rounds. The Weatherby is a long magnum round- same as the 300 H&H and 375 H&H. The 300 WM is a standard magnum round.
Not sure about the chamber, may need to ask your gunsmith or download the Saami specs to check it out.

Bob [/quote I agree, I think its a little more difficult than that I'm pretty sure it will have to be removed from the action to set proper headspace but I have been wrong before

Are the cartridge bases the same diameter? Might need to open the bolt face- I dunno, don't have a reloading book handy.

The action/ejection port are plenty long in the magnum 700 action for a full length Weatherby cartridge and they both have the same base diameter of .532".

Then the next thing you need to do is search for SAAMI drawings of the WM and the Weatherby and see how they match up. Should only take about 5 minutes.

Bob

It can be done but with all the experts responding, you need to take it to someone who knows what they are doing and not guessing about it. This is not a hand ream job!

Also remember that 300 WM factory ammo rund $45-75 a box. Muddy

You're being sarcastic right?

Muddy,

Yea, I know the steep price of Weatherby ammo. However I am somewhat of a brass hoarder and have about 150 pieces of brass. I also have dies as I load the round for my wife's uncle. I couldn't afford to shoot if I didn't handload!

Elk Country

i dont know if you could just lenghthen the chamber. would bet you would have to set back and rechamber.

Set back what?

The only reason to move the shoulder on the barrel tenon is to get the stamping to be indexed again. Otherwise, you can just ream it deeper until your headspace is correct.

You will not get a gunsmith to ream a chamber without removing the barrel to set head space if he does I wouldn't use him again. If your head space is set to big your brass is going to stretch and be junk I would want it to head space off of the shoulder not the belt.

I was always told the most belted magnums space off the belt. The biggest problem you'll run into with a rechamber of like cartridges is if one has more/less taper than the other. If so, the reamer won't clean up the old chamber and you'll have a chamber where the old shoulder is still existing while the new, deeper chamber runs past it, causing a false shoulder along with the new chamber. Pretty obvious the problems this can cause when the case expands after firing.

Haven't looked at the SAAMI drawings for these cartridges to see if this would be the case here, but as I said before to the OP, it would only take 5 minutes to do a search and find out.

I'm not sure I would be too impresssed with a smith who didn't remove the barrel for this procedure unless he had lots of experience and could convince me it would be done properly or he would fix it, quickly.

Bob

After looking at the SAAMI Drawings, it looks like the Weatherby will clean up the WM chamber. Still a good idea to let the gunsmith decide if the barrel needs a set back to clean it up completely.

Here is the link to the 300 WB drawings
http://www.saami.org/pubresources/cc_drawings/Rifle/300%20Weatherby%20Magnum.pdf

And here is the drawing for the 300 WM
300 Winchester Magnum
https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSPhggAVsaBlqEgZikdgmEkVd6Cc0Cv3LFM1SA1cFKETTAFcv9Y

Sheister,

According to the SAMMI drawing, it does head space on the front of the belt. I always size fired belted cases to just bump the shoulder back .001" to ensure the loaded rounds will function and some will say I'm using the shoulder to head space. I do it that way to minimize case stretching. I was pretty sure the Weatherby round would clean up the Win Mag chamber. I was just curious if I could do it with the barrel on the action or if I would have to take it to a gunsmith.

Shoot straight,

Elk Country

You could mark the back of the back of the chamber with dykum and SLOWLY hand turn the reamer till it marks the fluid. That should prove headspace is good. It's tricky doing the belted thing on the gun as your gauges will always prove ok till its to late.

By the time you rent a reamer and gauges you could pay someone most to do it....

W

Looking at the drawings, it looks like the shoulder difference is only about .120" or so. Of course, you also have to cut the Weatherby "double S" neck/shoulder but I don't think that would make a huge difference.
If my small lathe had a large enough bore, I would be tempted to try it a little at a time if I had access to a reamer. Worst that could happen is you take too much and you have to take it to a gunsmith to take it back a thread and recut the chamber.

Still shopping for larger lathe.....

Bob

Just get your Miketa drill, put an extension on your reamer and go to town. I wouldn't even take it out of the stock.

Of course you have to take the barrel off. I am just saying that this is not an AI where you do the .004" setback. There is no reason to touch the threads or tenon unless you want to index the barrel a certain way that is different than it now is. Simply run the reamer in until the case you plan to use fits. You can't go by the gage because they both headspace off the belt. Both use the same gage. You could have the reamer maker grind you a go-gage that goes off the shoulder if you want. I generally use a piece of factory brass that I have stored in my die box for setting up 300 Wby rechambers.

You can also mark the belt cut with ink and sneak up on it. Bottom line is that you don't need to 'set' anything back.

Instead trade in that entry level design for one with more features.

Features such as CRF, three position wing safety that controls the firing pin, solid attached bolt handle and bolt face, strong extractor and a quality look. The caliber will be wrong as marked on the barrel also.

Such makes are Mauser, M70, Ruger 77, Kimber etc.

Also the 300 Win mag is plenty big enough and more popular.

Broken 700 extractor in push feed.

You're still an idiot....

Yes, He sure is.

When building a rifle the 700 Remington action is my first choice .

+1

"When the debate is lost insults become the tool of the LOSER

Were these your bolts that broke or just some that you saw a photo of? No doubt the brazed on handles require some skill to assemble leaving room for failures but you can't fault the design for accuracy and safety.

I own and reload for both rounds and have owned both for several decades.

I think reaming the 300 Win chamber to 300 WBY is an exercise in futility.

In actual performance there is little difference between the two rounds when loaded to the same pressure in the same length barrel and zero difference that will be seen in the field.

Much more performance gains can be seen from bullet choice. With the higher BC bullets and powders available today the 300 Win can be loaded to deliver much more velocity and energy downrange than factory 300 Weatherby rounds.

It's also easier to find more sources of 300 Win brass.

Investing any money into a $10 Remy barrel except to replace it is a waste of money...if I take off a Remy barrel it gets recycled.

To all of you guys saying that removing a barrel is somehow required for a quality job....................hogwash!
I have and do many rifle re-chamberings without removing the barrel from the action, belted magnums being the easiest, generally.
The OP, the Weatherby chambering will completely clean up a Winchester chamber, the headspace will stay exactly the same if whoever does the job measures correctly, it should be .220" from the base to the forward section of the belt.

Cheers.

Best fit I found for the 300 wby is the sako L61 R.