Ailing question over the .300 Win Mag.

[Savage Fanatic]

This has been ailing me ever since I started reloading some 10-15 years ago.

How come the throat on a .300 Win Mag is always cut so deep yet the magazines as always is by far shorter. :?

 

[GB300wm]

I think short magazines is the rifle manufacturer. I have a Sako 75 in 300 win mag and my magazine box measures 3.750". I am able to seat 210 bergers 0.010" into the lands at a col of 3.360". So you see that it is the rifle manufacturer and their particular design that dictates the magazine box length. The throat is cut to spec for a 300 win mag in most cases unless the rifle has a different chamber for benchrest shooting or any other special purpose. :grin:

 

[GB300wm]

That's 3.630". sorry for the typo :grin: :grin:

 

[Desert Fox]

This has been ailing me ever since I started reloading some 10-15 years ago.

How come the throat on a .300 Win Mag is always cut so deep yet the magazines as always is by far shorter. :?

Don't sweat it. I have the same dilema when I first got my 300 Win Mag Model 70 Laredo. My throat measured 3.480 and my coal for the round to fit the magazine was 3.362 for a lead of .118. How does it shoot.

Here's some samples:

 

[nomosendero]

The Rem 700 has a long mag

 

[Savage Fanatic]

I just measured the throat on both of my .300 Win's too different manufactures.

And they both were throated at 3.56" and the mags are 3.38". Give or take a few thousandths.

Reading every manual I have all of them state the SAAMI max is 3.40". Why would they cut the throat deeper than the max, more what their intended box dimensions for the mag, is beyond me.

Last thing on my mind is scrutinizing the accuracy of one.

I am just curious as to why "in my case" would they create a situation where there would be almost 3/16" of bullet jump.

 

[SJB358]

Same here. My magazine box on my Ruger is just a hair longer than the Max length of 3.34. I pretty much load everything to that length to keep it easy. Rifle shoots really well, so I don't mess with it much. Scotty

 

[DrMike]

You describe a common feature of many manufacturers. COAL for Remington and Browning, for instance, is almost always restricted by magazine depth. On the other hand, Winchester magazines tend to be generous, allowing for loading longer cartridges. On the whole, magazines tend to be the limiting factor in COAL. Don't become overly concerned, as people have managed to develop some very accurate ammunition that is shot from Remington and Browning rifles (and Savage, and Kimber, and Weatherby, etc.). It is possible to gain a few thousandths of an inch by milling the magazine box, but usually there is little justification for the work.

 

[Ridge_Runner]

its to keep pressures down and velocity up, all weatherbys have alot of freebore.
RR

 

[woods]

The 300 win mag is the worst offender with the problem of not being able to load to the lands and still fit the magazine. I reload for a lot of rifles and have over 40 in my spreadsheet, 9 of them 300 win mags. A couple of years ago I wondered the same thing and then I realized that rifle manufacturers set their mag lengths for the other magnums like the 338, 7mm and 264 and that the 300 win mag case is longer than any of those

Now I have a Sako that has plenty of mag room and also a Beretta Mato that has plenty but Brownings, Savages and many others do not.

The ones with a short mag make great candidates for a rebarrel to 6.5 rem mag or 375 Ruger! :!:

 

[6mm Remington]

That's one of my pet peeves in the 6mm Remington, and probably works the same for the .257 Roberts and the 7mm Mauser since they all are on the same case. :evil: They often are chambered in a short action rifle when they really need a slightly longer action. A length of 3.00 is just about right for a magazine length for them. In my Remington 600 I can only go out as far as 2.825 which is the standard maximum listed for that cartridge. Thankfully in my son's Ruger MKII, its magazine is longer than the Remingtons. His 90 gr. E-tips are loaded at 2.840 and have enough room to the lands to be safe and fit with the information Nosler provided on loading them. With the 100 gr. Partitions, I am able to load those to 2.860 and they have enough room to feed just fine from the magazine.

 

[nomosendero]

As stated before, the Rem 700 is an exception, as it has a 375H&H length action. I wish the throat in my 300WM Sendero was a little longer so that I could utilize all of the mag length, still it let's me seat well beyond the factory stuff. The Rem is a great way to go to get the most out of the 300WM.

 

[3006savage]

I just measured the throat on both of my .300 Win's too different manufactures.

And they both were throated at 3.56" and the mags are 3.38". Give or take a few thousandths.

Reading every manual I have all of them state the SAAMI max is 3.40". Why would they cut the throat deeper than the max, more what their intended box dimensions for the mag, is beyond me.

Last thing on my mind is scrutinizing the accuracy of one.

I am just curious as to why "in my case" would they create a situation where there would be almost 3/16" of bullet jump.

The SAMMI max OAL for the 300 WM is 3.34". Depending on the bullet used having a long magazine length could result in the bullet being jammed into the lands when it is chambered. As ridge mentioned this will result in elevated pressures which could be a safety issue.

The design goal of the 300 WM was to maximized powder capacity in a 30-06 action length. They did this with a larger bolt face, longer brass, shorter neck, and sharper wider shoulder. This left less length for bullet seating and results in case encroachment problems.

You can probably get an aftermarket extended magazine for less than $50.00 to solve the problem.

 

[JD338]

The design goal of the 300 WM was to maximized powder capacity in a 30-06 action length. They did this with a larger bolt face, longer brass, shorter neck, and sharper wider shoulder. This left less length for bullet seating and results in case encroachment problems.

This is the very reason Nosler offers the 180 gr Partition Protected Point,
p/n 25396 BC .361 OAL 1.180"

JD338

 

[Savage Fanatic]

The design goal of the 300 WM was to maximized powder capacity in a 30-06 action length. They did this with a larger bolt face, longer brass, shorter neck, and sharper wider shoulder. This left less length for bullet seating and results in case encroachment problems.

This is the very reason Nosler offers the 180 gr Partition Protected Point,
p/n 25396 BC .361 OAL 1.180"

JD338

This very reason is why I use them and the BT's exclusively in my .300's. I just wish I wasn't limited to the "180gr" for the PPP's for this very reason.

Far as getting an extended magazine, I personally haven't looked down that avenue. Since both rifles are internal box magazines.