biggest of the SA's

HH .338

Active Member
Dec 14, 2002
biggest of the SA\'s

Good day,

I'm looking for some information concerning actions for WSM cartridges. I'm thinking of getting a 6.5 WSM set up for 140gr bullets. Which of the suitable short actions is the "biggest/longest" ie which action will allow me to seat the bullets out the farthest while still working in the mag.

Re: biggest of the SA\'s

I've built a couple of the 6.5 WSM now. What you are wanting to do is going to be tough. The 6.5 bullets are so long compared to others.
Even with a Wyatt's extended mag in a Rem. you would be seating the bullets really deep.
As much as I hate to admit it, Savage is one of the biggest SA and might be a little better than the Rem.
I don't suggest a Win. The lock time is just too slow for a 6.5 WSM. They have some definite ignition issues.
I still think that to fit in any SA mag, you might want to go to lighter, say 120grainers, without cutting into your case capacity.
The factory 300 even fits best with 150ish bullets. It really needs a medium action.
If you really want to stick with the heavy bullets, put it in a LA. Built a ton of 300 WSM in LA for guys shooting 190-210 in it.
Let me know, I can help you out with bullet selection, loads, etc. or even building it for you.
Re: biggest of the SA\'s

Thanks for the info Chris.
I hope I didn't used the wrong term but by SA I meant actions that come with factory rifles chambered for WSM cartridges. Not actions for 308 size cartridges. I really don't want to go with a LA but if the 6.5 WSM doesn't perform all that much better, then say a 260 AI, I really don't see the point. I have a 700 short action I could use for a 260 AI. Can 3000 fps be achieved out of a 24 in barrel using a WSM size action and 140gr bullets? Any idea what a 260 AI would do with that barrel length?

Re: biggest of the SA\'s

The actions are not longer than the .308 but they should be. They really should be built on a 30-06 length action. In order to shoot high ballistic coefficient bullets we have to short throat the barrel and extend the magazine length or live with a single shot. Even with the extended magazine length the bullets are seated deeper than I would like to see them. Too much lost powder capacity. With a 6.5mm I would imagine your problem would be even worse. My short action 6.5-284 single shot will not even let me extract an unfired case without pulling the bolt out of the action. I personally would not build another WSM on a short action. Any possible gain in accuracy from using the short action is just not worth the hassle. With hind sight being 20/20 I would have used a long action and long throated the barrel, seated those bullets way out there where they like to be, fill her up with powder and let the fur fly. Best of luck.
Re: biggest of the SA\'s

HH, The 6.5 WSM will get you 3100-3400 fps with the 140s, but like Weaverism and I said you can't really do it in a SA repeater. The Wyatt box gives enough room in the 300 for 190s at 2900 fps (see WyoWhispers thread) but the 140 6.5 bullets are a mile long.

You missed one thing on the difference in a SA 308 or 300- feeding- rails mag box and follower are different.

The best SA repeater cartridge probably is the 260 AI but you still can't get 6.5-284 or WSM velocities with the 140s.
Either go single shot or into a LA.
Re: biggest of the SA\'s

You can modify an exsisting action so that your magazine well is longer.
You must mill out the rear most portion of the action but leave appx .050 between the new rear magazine well length and the front mounting trigger hole location. You will probably end up with .5 length increase, you must also mill off this same distance off of your bolt stop lever or install a button type from Sinclair INT.
You then have to make a new stamped magazine well insert.
I have done this and its relativly easy if your a machinist if not then a competent gunsmith should be able to perform it for a resonable cost.
Re: biggest of the SA\'s

Let's see if I've got this straight. The Wyatt box allows a .300 WSM to achieve 2900 fps. with a 190 VLD seated out to the box maximum length, right? But with a 140 VLD you can't achieve a similar goal because the bullets are too long?

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>The Wyatt box gives enough room in the 300 for 190s at 2900 fps (see WyoWhispers thread) but the 140 6.5 bullets are a mile long.
If we are given the box length equal to 3.100" and a cartridge OAL of 3.100 with a cartridge capacity of 79.0 grains (approx.) and we take the longest 30 cal. 190 grain bullet of 1.380" (Berger VLD) and seat it to 3.1" that leaves about .380 total length in the case with .190 of that as shank. This leaves 72.499 grains of available capacity. I get about 2900 fps. with several powders in a 24" barrel. This is full capacity at max. pressure.

Now, if I take the same case necked down to .264 with a case capacity of 79.0 grains of H2O and pick the longest 140 grain bullet (Berger VLD @ 1.348") and seat it to the same 3.1" OAL then that leaves me with .348" bullet length in the case and .138" of that being shank. Case capacity remaining is 74.855 grains. My calculation come up with about 3125 fps. with several powders at full capacity at max. pressure.

How much less of these bullets do you want in the case? I consider 0.190" and 0.138" of shank length to be pretty minimal. So where is the problem with the 140's?


[ 12-24-2003: Message edited by: Crispin Goodall ]

[ 12-24-2003: Message edited by: Crispin Goodall ]
Re: biggest of the SA\'s

I did a search on the net and it seems the only thing different between a 308 size action and a 300 wsm size action is the size of the bolt face. For some reason I always thought that the WSM actions where longer.
Re: biggest of the SA\'s


I am not using Berger VLD's they would never fit in the Wyatts box unless they were seated deep into the case.
I use the SMK's and are not as long as the VLD's
Re: biggest of the SA\'s

I like to seat the bullet at the start of the boattail at the bottom of the neck. Anything further I think is too deep. Just my opinion. At this seating depth the 6.5 with a 142 MatchKing will not fit in a Wyatts extended box. Like Ric said a 190 MK in 300 will.
Why seat it so deep in the 6.5 WSM that you can't use the full potential of it. True, Ric's best accuracy with his 6.5 was around 3100, but I now a ouple of guys winning consistantly at 1000 yards pushing bullets at 3400.
The whole point is the 300 WSM barely fits into a SA. Winchester designed it for 150 gr bullets.
To equal 300 Win Mag performance modifications have to be made, ie the Wyatts mag box or go single shot.
The 6.5 WSM is a 1000 yard benchrest round (read single shot) It was not designed for a repeating varminter style rifle.
If he really wants a repeater in a SA he will have to use 120 or lighter bullets.
Just my experience with em
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