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Tikka T3, .243 & Sierra Gameking 100g 1560 SP

13 Sep 2015
@ 01:44 pm (GMT)

tim bugg

My rifle currently shoots .4 to .6” with federal powershock 100G SP

I picked the Sierra Gameking 1560 100G boat tailed SP bullet as I wanted good expansion 300yrd+ and we have to use 100G for deer in Scotland but our estate doesn’t like plastic tipped.

I have been through the loads in .5grain increments both at 10, 30 thou off lands, recommended by several other. Then 100thou off as this is same as federal PS.

I did get one good group .4” @ 10thou and explored round this in .2grain increments but on the day (colder than previous) results were rubbish again.

The groups are generally 1.5” sometime bigger ! and also move POI of group up and down by 1 to 1.5".

I did pull some tighter today say 1” but at hi pressure (smiley face jobs)

Am I wasting my time with this bullet. Is it just not stabilizing?

Any help would be appreciated.


13 Sep 2015
@ 07:20 pm (GMT)

Bryan Webster

Re: Tikka T3, .243 & Sierra Gameking 100g 1560 SP
Tikka T3 rifles in .243 Win. have a 1 in 10 twist, while a few other brands have faster twists. My old heavy barrelled Sako Forester .243 did not really like 100 to 105 grain bullets but I loaded hot and kept groups around 1 inch @ 100 yards, which was fine for mule and white-tailed deer. The Sierra 85 Gr hpbt would shoot in 0,3 to 0.4 inch groups and was consistent. Used these for targets and coyotes.

If using a .243 I would be hesitant to shoot anything larger than a mule deer at overly long ranges, and would restrict my shots to 300 or so personally. I suggest you try Nosler 100 grain partitions or the Speer 105 grain bullets. Given the accuracy you mentioned it seems to me these bullets loaded to what your rifle considers near maximum should give you enough accuracy to be very effective for shooting game that size.

You could possibly obtain a Rifle with a 1 in 8 twist to try the longer bullets. Recommend you visit Berger bullets and see their recommended twist rate for their hunting vld at 1 in 8 twist rate.

Good luck with this.
13 Sep 2015
@ 09:46 pm (GMT)

Nathan Foster

Re: Tikka T3, .243 & Sierra Gameking 100g 1560 SP
Hi Tim, it is of course hard for me to say anything without having the rifle in hand. So, all I can do is guess.

1. Make sure the ammo is concentric as per my reloading book. This may be a key factor.
2. Make sure you have the max COAL's correct and recorded for the individual bullet as per my reloading book. All the same, I want you to sit this one at 1mm jump due to potential bullet to bullet variations. Check also that the boat tail junction is at least flush with the bottom of the case neck rather than sitting out into the case neck.
3. What did you mean by high pressure? Do you mean that it was a max load as per the reloading manuals or a max load for your actual rifle- as in primer pockets swelling.

The GK is generally easy to work with but groups of +1.5" sound pretty bad compared to what you have been seeing with Federal ammo. I cannot say any more until you have been through the above and checked everything carefully.

Off topic, you can see why I recommended Federal as an option among the preliminary test sections of my Accurizing book.

It is a pity that your estate does not like plastic tipped bullets. Perhaps you could take them a new paper with the date on it and let someone know that it is in fact 2015, not 1815.

Bryan, the .243 became popular in the UK due to game keepers using it in the off season to neck shoot deer for the chiller trade. As you can imagine, the rifles where generally easy to shoot, not too much recoil interia to the platform, making accurate neck shooting quite possible. Somehow, the .243 has expanded vastly beyond this role. I think perhaps because it is an ideal cartridge for Roe deer. But as you say, things can get dicey when shooting an animal close to the size of an Elk at extended ranges. The tundra country up in Scotland offers some dead ground for stalking but quite often you can't get in close due to the open terrain. The tundra grasses can be very long (sometimes a total clusterf), making shots difficult if you can't get a good prone position. Shooting sticks are common, heavy shooting tripods not so common. As can be expected, if a solid rest cannot be obtained, exact shot placement cannot be obtained either. So, a bit more power can be useful.

There is plenty of bullshit to be had here because some guides in the UK get pissy when hunters break down the shoulders on an animal. Your suggestion that Tim run a Partition is similar to my assertion along with the goal of breaking the animal down in a locamotive sense. But Tim may be faced with a "why did you ruin the meat" hollering. But if he aims too far back and the guide has to go for a big recovery walk, he'll probably get a hollering over that too.
14 Sep 2015
@ 07:37 am (GMT)

Mike Davis

Re: Tikka T3, .243 & Sierra Gameking 100g 1560 SP
Ive never been a huge fan of the twoforfree/EBRG but will admit 95% of all the game Ive shot over the years would have gone down just as well with it.
as for pissy guides not wanting shoulders broken as it ruins meat!!!!!! give them a mincer for xmas and eat right up to the bullet hole.
14 Sep 2015
@ 08:06 pm (GMT)

Bryan Webster

Re: Tikka T3, .243 & Sierra Gameking 100g 1560 SP
Hello Nathan. I used to shoot a Sako Forester heavy Barelled .243 Win for work as well as hunting. Took many whitetail and mule deer along with 14 elk and one moose. I used 100 gr partition bullets for the elk and moose even though it would only do 1 to 1.5 inch groups with it at 100 yards, so I held back on long shots because of that plus not wanting to wound if the bullet failed to perform as expected. I spent a lot of time and effort trying to make that rifle love those 100 gr partitions as well as other 100 grain products to no avail, but in the meantime was able to head shoot yellow belly marmots out to 500 meters with the gun using 85 gr match loads.

That rifle would shoot 0.25 to 0.3 inch groups under good conditions with the Sierra 85 gr hpbt and did sub .5 with many of the other brands' lighter bullets as well, hence my thoughts on rifle twist using the 100 to 105 grain bullets.

A friend had I think a Winchester featherweight (cannot be sure of the make as it was 42 years ago) but I do know it had a 1 in 8 twist, and he had no issues at all with getting the Nosler 100 grainers to group very well after we used Bisonite to bed his rifle.

Anyways, just some thoughts on this as I am also in the process of building a .243 for a grandson's first rifle and appreciate hearing anything about the round. He is a dyed in the wool left hander with an inability to use his right eye to shoot, so to begin with I thought about the T3 but decided to use a lija barrel on it with a different twist than 1 in 10.


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