243 Winchester Revisited

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Last Post 20 April 2018

CBA Member

Bohica793 posted this 26 March 2018

After following Jim Scearcy’s chronicle of his experiences with the 243 and cast bullets, I decided to dive down this rabbit hole myself. I have signed up for both the Spring Warm-up and the 200 yards combined postal matches (among a number of others) and plan to use my cheap little Ruger American 243 with a 1 in 9 twist. My only mold for this undertaking is an RCBS 243-95 which, so far, has produced absolutely beautiful little pills cast from WW+2% that I size to .244, gas check and lube with Carnauba Red from White Lubes.

For my starting point, I am using Lyman 49’s recommended accuracy load of 13.5 grains of IMR-4198 loaded to an OAL of 2.610. I loaded 20 of these and ran 15 of them across my chronograph to a 25 yd target. The results are promising. The load averaged 1600 fps with a standard deviation just under 20. I attribute some of this variation to the fact that I user mixed, untrimmed and unsorted brass for this test.

Running the data through the ballistics calculator shows that this load, while good at 100 yards, would be transonic at the 200 yards mark. I will need to bump the velocity at least another 100 fps to maintain supersonic out to 200 yards. My next tests will involve raising the powder charge in half grain increments from 14.0 to 16.0 grains and shooting 10 shot groups at 100 yards. I’ll then take the best from that out to 200 and see what it will do.

Film at 11……..

243

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Standard Member

OU812 posted this 26 March 2018

Verygood and thanks for posting.

I learned I may need to reduce my 4198 powder charge in the 223 Remington. Been using 14-15 grains but probably need to be in 11-13 grain range with the 60 grain LBT bullet.

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CBA Member

Bohica793 posted this 27 March 2018

Went to the range today with the intent of shooting 10-shot groups with charges of 14.0 through 16.0 of IMR-4198. Ended up only shooting the 14.0 and 14.5 loads with marginal success as I was having difficulty chambering rounds. Upon closer inspection, it appears that the top punch I am using is slightly deforming my bullets causing chambering issues. I have the proper top punch on order and it should be delivered before the end of the week. Meanwhile, I am pulling everything, re-pouring and starting over.

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Standard Member

OU812 posted this 28 March 2018

That's right...blame it on the nose punch. What nose punch worked in the group that is pictured.

Was this a seating top punch or a sizing top punch

Sizing bullets base first will cause "fresh cast soft bullets" to deform or make bore ride section larger. You should let bullets age harden a couple of days before sizing...base first.

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CBA Member

Bohica793 posted this 28 March 2018

Sizing punch was the culpret and I did probably size these too soon after pouring. Lesson learned.

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CBA Member

Scearcy posted this 28 March 2018

Bohica793

It is great to see you work! 13.5 gr of IMR 4198 was the sweet spot for me although in 2007 the Nationals were won using 17.0 gr of IMR 4198. My problem of course was that my most accurate rifle has 1x10" twist and I could not keep the 100 gr NOE bullet stable at 200 yards. I either need faster twist or more velocity.

Match your alloy to your velocity. The 243 seems more sensitive to that match than my 30 cals have been.

Jim

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CBA Member

Bohica793 posted this 28 March 2018

I don't have the NOE mold but I just picked up a Lyman 245497 off of another form to play with. I am a firm believer that WW+2% in the 12-16 BHN range with work perfectly well in any load up to 2200fps if properly sized and lubed Still a lot of work left to do and more lessons to learn.

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CBA Member

Eutectic posted this 28 March 2018

I gave up on factory nose punches. Some from Lyman which were supposed to fit did not.

For serious work, I coat a bullet with floor wax and put epoxy putty in a factory nose punch.
I let it set up in the lube-sizer or seating die. The result is a perfect fit.

This also works great for hollow point bullets which are easily distorted in sizing and seating.

Steve

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CBA Member

Scearcy posted this 19 April 2018

Bohica793

Just checking in on your progress. I made 1,100 6MM bullets this past week and I am ready to try to improve on last years results. I have almost 2 years of Cabelas points accumulated and have been admiring their Henry single shot in 243 also. NOEs Eagan style 80 gr bullet at about 1100-1200 fps should be a very good plinker load.

Jim

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CBA Member

Bohica793 posted this 19 April 2018

I am still looking for the magic load. I have been experimenting with the RCBS 243-95 as well as an Ideal 245497 with limited success. Best groups at 100 yards so far are 1.5-2". I just mailed my targets for the Spring Warm-up which were less than stellar with 17.1 grains of IMR4198 and the RCBS bullet. After I shoot my military targets next week, I will go back to this and start playing with bullet seating.

I did get kind of distracted, though, as I just acquired a Ruger Precision in 6mm Creedmoor and have been shooting 2" groups at 200 yards with it (jacketed). Did a 100 yard OCW ladder with the largest group being .85" and the smallest being .117. So much fun,,,,,