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Longer OAL for 300WinMag?
Posted by DND on February 11, 2013 at 5:18 pmGreetings! New member, first post.
I'm currently running a Tikka Tac 300 Win Mag in a Manners T4 stock, plus various assorted bits. Load development indicates it wants a longer OAL than the factory mags are capable accepting. Aftermarket DBMs for long actions seem scarce. Am I correct that CDI is the only option? Also with the CDI, my research indicates the additional OAL length the AI mags are able to provide cannot be utilized as the DBM is designed in such a way as to restrict length to standard spec.
Thoughts and suggestions are welcome. I believe the rifle has decent potential but is hindered by this seemingly common hurdle.
Cheers,
DaveJ replied 8 years, 10 months ago 5 Members · 5 Replies -
5 Replies
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1 Bullseye
Okay, 254 views but no discussion. If there is any interest, I have found a solution to allow longer OAL that is working in my rifle, hopefully it may help others.
Since I started this thread back in February I've added a CDI DBM to my rifle and now found a way to allow cartridges with a longer than SAAMI spec to feed reliably. So far I've found lengths out to the max OAL the AI mag can accommodate of 3.65″ to feed well. The problem experienced was the new cartridge being pushed forward by the bolt was jamming since it was only allowed to move straight forward instead of forward and angle upward. The solution was to have the new cartridge angled upward while still retained in the magazine, which in turn avoided the jam as it was moved forward.
Clear as mud?
Okay, pics and a hopefully explanatory tutorial –
The overall goal is to raise the shoulder and neck of the case in order to facilitate chambering instead of jamming a longer than SAAMI OAL 300WM round in a Tikka T3 action. Image 1 depicts me holding a casing in roughly the stock orientation of an un-modified AI mag on the left. Note how the body of the casing is roughly parallel with the magazine lips. The mag on the right shows how the casing now sits shoulder and neck high and will feed reliably in my action.
Image 1 –
The front (directly under bullet) of the stock AI magazine follower is limited in the height it can reach by two small tabs as depicted in image 2.
Image 2-
With these tabs bent up approximately 1/8″ on mine, the front of the follower is now visibly higher than stock. In image 3 I am holding the follower on the left mag in roughly the stock position while the mag on the right is at the new raised height. Note the notch at the front of the follower on the right mag is visible for reference. No notch showing on the left mag.
Image 3 –
Now that the follower is allowed to travel to the height we want it, the new limiting factor for rounds is the magazine lips that retain the casing. By bending the leading 2/3 of the two lips outward approximately 1/16″ each side the casing is now allowed to travel to the height the follower will go to under spring tension. This is harder to see, but in image 4 I am pointing with the screwdriver to the point where the lips start being bent outward, all the way to the front or upward in the image. The rear 1/3 of the lips are not changed which holds the case head in the stock position and properly oriented with the bolt.
Image 4-
Image 5 includes a casing to help see where the tapered bend of the lips begins.
Image 5-
All bends were accomplished with hand tools, specifically lineman's pliers while holding the magazine by hand.
I hope this helps anyone looking to run longer OAL in their Tikka T3 and I'll gladly address any questions to the best of my ability.
Cheers,
Dave -
1 Bullseye
I understand what you are going through.
For what its worth, it seems that the ideal OAL of the 300WinMag varies quite a bit from one brand of rifle to another.
While My T3 308 is happy with the nominal spec OAL my Remington Sendero 300WM wants it a lot longer than any of the factory loads, but shorter than a friends ideal Winchester 300WM loads, which mine shoots well, but which fit too tightly to be an everyday field load.
This fact forces you to be a reloader or know a good one. -
1 Bullseye
I'm in the process of building a long range tactical rig Tikka T3 in 300 Win Mag and have the exact same issues regarding magazine OAL. Thanks for posting this as I am now aware of on option for longer OAL mag.
Cheers
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1 Bullseye
This is an old post, but there are some newer options on the market.
Atlasworxs LA, AI compatible DBM is now on the market from coretac solutions for $210 Canadian.
TPC say they will soon offer a LA DBM which will take the 3.6 OAL AI mags for .300 Win Mag. I'm waiting for them to appear to complete my build.
Either way, I guess the action limitations will require mag modification as described very well above.
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