I have a 243w for my Blaser but it seems to dislike most of the bullets, I would like to go with the Barnes TSX but I can’t get sub MOA accuracy with it.
Has anyone in the same situation tried to change calibre (243AI or 6mm-284) on the same barrel and the achieved better accuracy?

The TSX is a rather long bullet, and your rifle's 1:10 twist rate is not exactly optimum for this projectile, though in theory it should be OK (I personally like the 1:8 for the .243 Win and 6mm Rem).

Re-chambering may not necessarily affect anything positively, but it probably can't hurt, either.

Also, have you checked the crown? A miniscule burr or simply a non-concentric "cut" can wreak havoc on accuracy.

I'd suggest trying a few other bullets/powders before rechambering. It could be that your rifle simple doesn't like the load combo you're currently feeding it.

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The TSX is a rather long bullet, and your rifle's 1:10 twist rate is not exactly optimum for this projectile, though in theory it should be OK (I personally like the 1:8 for the .243 Win and 6mm Rem).

Yes it's 1:10 but according to twist rate lists from Lilja & Shilen it should be fine up to 100 grain (my rifle shoot sub MOA with 100 grain Hornady BTSP) and the TSX bullet is just 1mm shorter than Hornady 100 grain BTSP

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I'd suggest trying a few other bullets/powders before rechambering. It could be that your rifle simple doesn't like the load combo you're currently feeding it.

I've tried other powders - seatings - primers, the rifle also shoot sub MOA with Hornady 87 grain BTHP and 90 grain Speer Hot-Cor

I would prefer the 22-250 for my hunt but we are not allowed to use smaller calibre than 6mm on roe deer in England, I should maybe try the 25-06 instead?

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I'd suggest trying a few other bullets/powders before rechambering.

I would try the new 80 TTSX before rechambering, but i was wondering if it was the 243w that has bad accuracy and it would help to convert to another 6mm case?

Although I have zero experience with a 243 Win, I do have some experience with the 244Rem/6mm Rem. The bullets that shoot well in my 6mm Rem are the 95 or 100 grain Nosler Partitions, and an 80 grain Berger. These bullets with the right powder/charge will deliver 3 shots into 1/2" groups at 100 yards, with a 20x scope I use for load developing.

Don

BlaserGun wrote:

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my rifle shoot sub MOA with 100 grain Hornady BTSP

There is nothing inherently "inaccurate" about the .243 WCF, as your sub-MOA loads with other bullets attest.

Some guns just are finicky about loads/bullets. Also, Barnes bullets often do best when the bore is completely free of any copper fouling. Give your rifle a good cleaning, and give them a whirl again.

On the other hand, the bullets you mention that your rifle does well with would serve your purposes just fine.

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On the other hand, the bullets you mention that your rifle does well with would serve your purposes just fine.

I tried them on roe deer and I dislike the result, I would classify them to more as varmint bullets than game bullets for the 243w, the TSX does a very nice job

Then I would try and get all the fouling out of the bore and give the TSXs another try.

Let us know how this works out.

Bobby

Even a 24h cure with bore foam didn’t make it more accurate, but I think I’m done with the 6mm calibres, I better go with a 25-06 and pray for better accuracy

Try 95gr Nosler Partitions or 100gr Sierras wth 40 to 42gr of IMR 4350 in your 243.

The Barnes X bullets are very barrel sensitive.

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Then I would try and get all the fouling out of the bore and give the TSXs another try.

I use Forrest bore foam to get rid of fouling and I've now added 36 hours cure while a patch is still dirty when I run it trough the barrel to clean out the foam, I'll continue the foam cure until it comes out clean and let you know.
I'll be in Norway for next week going for beaver, and if the 243 will not perform, then I'll use my 6,5x55 match barrel instead

Make sure to let us know how the "beaver" hunt goes!! (I Couldn't help it friends!! It just popped into mind!!) GHD

Blasers are normaly very accurate (my two barrels were very easy to get well under MOA)Mine haven't copper fouled much.

Blaming a calibre for not liking TSXs is unfair. It's a pain when an accurate rifle doesn't like the bullet you want to use but not much can be done about it. I doubt rechambering etc will change it.

Forest bore foam is not very strong so you may still have gilding metal jacket fouling.

O.K. There is a break down in communications here. The twist charts assume bullets of jacketed lead which implies a certain length. "Width" is established by bore diameter. You go to a solid copper bullet like the TSX and you move away from these standards. Longer bullet for the weight. The 100 grain bullet may be too long for best accuracy in a 1 in 10.

You have choices. Is there a slightly lighter TSX that would meet your needs and not be as long? 85 grains? 90 grains? Or you can go to the shorter lead, jacketed bullets. Look at a catalogue. Many.

A re chamber is "iffy." If you are not getting enough "spin" with current twist will the additional velocity get you into minimum spin rate for best accuracy with this bullet? You could query barrel makers. AND unless there is a defect in the current barrel that the rechamber removes, improvement in accuracy is not likely to be great.

I got a head ache over the arithmetic the first time I went over it and try to stay away since.

1 in 12 and velocity of 3,000 feet per second is 3,000 turns per second. 1 in 6 would give 6,000 turns per second. The heating of the bullet by air resistance is hard to measure but many recommend a harder core in high velocity bullets (with lead core). Copper would avoid this, but... LUCK. Enjoy the beaver hunting.

Oh yes, my gunsmith, now retired, was "goofy" over the 6mm/.284. It had "the hottest" and the most accurate... he would build one and someone would see it shoot and out came the money and he was building another... Has everything but barrel life. You burn that much powder and you burn the barrel too. He would load by dipping case in IMR4350 and seating a bullet, varmint bullets anyway. Like mine. luck.

A picture of the accuracy with TSX in my 243



A 24 hour cure didn't change much, but today after I think 4 or 5 cures soaked in with bore foam and a finish polish with Gold Medalion it was back in business again (they are both 5 shot groups)



I should maybe ask a gunsmith to check the crown??

I have shot the sierra 85gr bthp in every 243 I have owned. I have never been disappointed with its accuracy or performance on game. I have a half dozen hunting buddies who will shoot no other bullet. They ALL shoot IMR 4831. 44.5 grs up or down a couple of tenths. If it wont shoot that, buy a remington, it will. (just funnin ya) But it really will.

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Originally posted by BlaserGun:

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I'd suggest trying a few other bullets/powders before rechambering.

I would try the new 80 TTSX before rechambering, but i was wondering if it was the 243w that has bad accuracy and it would help to convert to another 6mm case?

The 243 has a rep as a tackdriver, but I have never hand much luck with the chambering. However, my 6mm/284 is capable of one-hole grouping with max loads.......

a lesson learned...
your gun just likes a clean bore! some will actually shoot better dirty. just another thing to consider part of load development. my 7x57 imp'd shoots it's best group after about 6-8 shots down the bore, but then starts to open up after about about 20 again.
a question for those who know.... is that generally a sign of a rough bore?
in it's "good shooting" state of dirtiness it will group right around 1-1/4 inches. it has a fairly light barrel contour...620" at the muzzle, a sliver of a forearm and my own (ameture) bedding job (my first attempt as well), so i don't think it can get much better.