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300 Win Mag or 300 RCM with 20" Barrel

17 May 2013
@ 05:16 am (GMT)

Mark Whitaker


Ruger has just produced their new "Guide Gun" and I am seriously looking to getting one for pigs here in FNQ and the NT. I would scope it with either a Sightron 1-7 or a Minox ZA5 1.8-8x32. Both scopes would be good for close range and also capable for shots up to 500 yards if needed.

I think Ruger has hit the nail on the head with this rifle.

I believe the 300 RCM would be the better choice with a 20" barrel but brass is non-exsistant here in Australia and very rare in the US (non listed at at the moment).

Muzzle flash when used spotlighting would be reduced (not eliminated) with the 300 RCM compared to the 300 Win Mag. (???)

My question is to reduce muzzle flash with the 300 Win Mag, is it achievable with this calibre using a faster powder, AR2209 or even AR2208 and still be usable round for longer range?

I would start with A-Max 208gr.

Is it worth it at all with the 20" barrel? Or should I just try and get as much 300 RCM brass as I can?

Thanks Mark


17 May 2013
@ 06:17 am (GMT)

trevor savage

Re: 300 Win Mag or 300 RCM with 20" Barrel
i had a 300 win mag, cut it down to 20" and it was a loud beast and huge flash without the suppressor on it. the suppressor did cut out the flash.
the trusty old .308 might be a good choice but thats just my two cents.
as i understand it the magnums need the extra long barrels to burn all the powder and get the higher velocity's.
17 May 2013
@ 03:15 pm (GMT)

Mark Whitaker

Re: 300 Win Mag or 300 RCM with 20" Barrel
Thanks Trevor, but I already has a 7mm-08 so no need for a 308.

What I am after is, is it worth pursuing or as the Ruger platform seems good.

If I go for anything else its a rebarrel and more expense. No one else makes a short barrel magnum with overall weight in the 8lbs+
17 May 2013
@ 06:15 pm (GMT)

Nathan Foster

Re: 300 Win Mag or 300 RCM with 20" Barrel
Hi Mark, I am perhaps not a good person to ask about this sort of this sort of thing. My fast handling pig rifle is a short heavy barreled .308. Recoil is low enough that I can get back on track very quickly for repeat shots if I am asked to cull. I take several shots without heat effecting the barrel. I can shoot out to long ranges with this rig. That's one set up.

A friend of mine runs a Tikka T3 in .300 WSM for maximum power from a short and light platform. The rig works extremely well. But- he has to really be on his game to shoot with precision accuracy at long ranges. It is a lot of recoil. Felt recoil is fine, but the effect of recoil on accuracy if technique is anything less than optimal is pronounced. So there is a time factor involved, getting into position, making sure everything is in order if taking long shots. It is simply a matter of physics. I don't see any need for a 20" barrel in this regard, the T3 rifle is handy enough, any shorter or lighter an it would be difficult to use. Hell, 20 years ago a handy rifle was an SMLE with the wood removed- 25" barrel.

OK, so that's another example of another persons compact rig with reach.

I don't know enough about the .300RCM to be reliable or confident in my advice Mark. All I have is questions, not answers.

The .300RCM delivers its performance utilizing Superformance powder. Without SF powder, it has similar power and potential to the .300 SAUM- which is a very good cartridge in its own right. Lots of power from a compact rifle for sure. Hand loads from a 20" barrel appear to duplicate .300 RSAUM loads from a 22" barrel- 3130fps with 150 grain bullets, 2930fps with 165 grain bullets, 2830fps with 180 grain bullets, 2630fps with 200 grain bullets and 2530fps with 208/210 grain bullets.

Ok, so we know the cartridge has power potential. Below are my concerns with regard to what you are wanting:

I do not know whether the Ruger magazine length will be complimentary to the use of the 208gr A-max. If the magazine is a standard 72mm and ammo has to be seated to 71mm for smooth feeding, the ogive of the A-max will be well into the case neck. I can just seat a 208gr A-max in the .308Win for kicks, if I stretch the COAL out to 71.2mm.

I do not know how much freebore is utilized and the effect this will have on load development for long range accuracy at high velocities.

There is a high possibility that you will have to go through a full accurizing process before you can shoot the rifle. Trigger work, bedding, lap bolt locking lugs. Rifle should be good to go after giving it the works.

Recoil is always an issue in light weight rifles / magnum chamberings. Felt recoil may well be fine, just a matter of monitoring field technique versus accuracy.

I don't think the .300 WM is completely necessary or useful when spot lighting.

A .30-06 could be very useful and simple.

Muzzle flash will be an issue with many rigs. It is possible to step down to 2208/Varget in the short mags and reduce loads. By the same token, 2206H in the .308Win is fast burning.

You won't see too many commercial spot lighters using 1-7 x24 optics, even at ranges as close as 10 yards. Light gathering tends to be very poor with the small objective. In NZ, standard optics are 4x32 and 4x40 units, I have used both for commercial work at night. If you want to be able to shoot long, a 3-12 or 4-16 would be ideal, dialed down to 4 power for night work or 6 power if shooting from a cherry picker across cane fields etc.

Not much help sorry, I simply don't have experience with the .300 RCM. I can see the merits in the concept though. The example I gave of my heavy short barreled .308 is not meant to indicate that my culling rig is 'better' than your idea of adopting the .300RCM, Just wanted you to be able to look at this from different angles and explore what it might take to get the rig shooting accuractely. The short magnums have great power and deal a heavy blow at close and long ranges.

17 May 2013
@ 10:54 pm (GMT)

Mark Whitaker

Re: 300 Win Mag or 300 RCM with 20" Barrel
Thanks Nathan, you brought up all the same reasons for not going 300WM in this platform as I have, plus a few more. COL was one of my big concerns.

One of the draws to this rifle is its weight, its not a light weight at 8lbs sans scope and base. With its muzzle brake it "should" be a manageable rilfe.

At the moment there are none in the country, all back-ordered with no arrival date and no 300RCM back-orderd.

The only reason I was looking at the 300WM is I picked up 140 rounds of Norma 168gr SP factory rounds for $36 a box last year. A bargain I could not pass up, but nothing to feed it too!


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