Tikka .243 AI

[eric1115]

120ish rounds through the gun now, barrel has sped up to 3150 for the 106 with intermittent slight pressure signs at 50.5. Groups have opened up a bit too, so I've got 15 each at 50.0 and 49.5 to see if I can bring it back down a bit and be a bit happier.

 

[eric1115]

Interestingly, dropping a grain didn't change velocity very much, 3130 5 round average. 10 rounds at 49.5 printed this group, and the one high round showed ejector mark on the brass. Wind has been whipping and gusty, to the point of disrupting steady sight picture at times.

 

[AZ_Hunter]

Great thread. Please keep us updated, I’m seriously thinking about copying you.

 

[eric1115]

I've shot a couple hundred rounds at 47.0 gr H1000, 3050 fps, and I think I'm going to drop another ½ grain (or buy some new brass and re-work)... I've lost a few primers and occasionally still get ejector marks (got some supposedly lightly loaded 2-3x fired Lapua brass already AI formed, and it's been a bit of a headache)

I've been super happy with it, but deep down I think I would have been better served by a 6CM or straight .243win. I have more money into Redding dies and rechamber than I would have into a PBB 6CM and Hornady or RCBS dies. Part of this is my own doing, got a wee bit carried away and ended up (almost by accident, long story) with Redding competition micrometer seater, neck, and FL dies and $100 in bushings and VLD seater stem. Probably close to $500 wrapped up in dies. If they were all purchased new.

Can't deny that the .243AI looks incredibly cool with a 106 seated long, and that's really the most important thing.

If I were going to do .243AI again I would 100% rethink my die setup. Type S FL, and probably do a little more research on seating dies. I think the basic ones from Redding don't allow the use of a VLD stem which would be a deal breaker if true.

All that said, zero regrets selling off my 7mmRM and committing to this as my new all range all species hunting rifle. Great shooting, easy shot spotting, great suppressed, I love it.

 

[sveltri]

I've shot a couple hundred rounds at 47.0 gr H1000, 3050 fps, and I think I'm going to drop another ½ grain (or buy some new brass and re-work)... I've lost a few primers and occasionally still get ejector marks (got some supposedly lightly loaded 2-3x fired Lapua brass already AI formed, and it's been a bit of a headache)

I've been super happy with it, but deep down I think I would have been better served by a 6CM or straight .243win. I have more money into Redding dies and rechamber than I would have into a PBB 6CM and Hornady or RCBS dies. Part of this is my own doing, got a wee bit carried away and ended up (almost by accident, long story) with Redding competition micrometer seater, neck, and FL dies and $100 in bushings and VLD seater stem. Probably close to $500 wrapped up in dies. If they were all purchased new.

Can't deny that the .243AI looks incredibly cool with a 106 seated long, and that's really the most important thing.

If I were going to do .243AI again I would 100% rethink my die setup. Type S FL, and probably do a little more research on seating dies. I think the basic ones from Redding don't allow the use of a VLD stem which would be a deal breaker if true.

All that said, zero regrets selling off my 7mmRM and committing to this as my new all range all species hunting rifle. Great shooting, easy shot spotting, great suppressed, I love it.

Sorry to hear your experience isn't going great. I guess I've been fortunate, I'm at 50ish grains H1000 with the 108's at 3100 no pressure signs at all, even at 90 degrees. I went fairly cheap on the dies and got the Lee 243 collet die and a Redding type S with the button removed. So far everything has been good. I do have to clean this gun fairly regular or I get carbon ring. Have you looked inside with a bore scope yet?

 

[wind gypsy]

Sorry to hear your experience isn't going great. I guess I've been fortunate, I'm at 50ish grains H1000 with the 108's at 3100 no pressure signs at all, even at 90 degrees. I went fairly cheap on the dies and got the Lee 243 collet die and a Redding type S with the button removed. So far everything has been good. I do have to clean this gun fairly regular or I get carbon ring. Have you looked inside with a bore scope yet?

My first thought was if @eric1115 is going the no cleaning route and that being tied to him having to frequently reduce his powder charge.

 

[pods8 (Rugged Stitching)]

I've been super happy with it, but deep down I think I would have been better served by a 6CM or straight .243win.

Aside from the dies and all that there is no denying, imho, that fire forming brass sucks in general and worse yet if its on a barrel with a shorter lifespan. Someone will chime in "practice" for the fire forming, yeah yeah, still annoying. Being able to just buy 6cm brass from a good supplier is what keeps repeating in my head each time I wonder about 243AI.

 

[sveltri]

Aside from the dies and all that there is no denying, imho, that fire forming brass sucks in general and worse yet if its on a barrel with a shorter lifespan. Someone will chime in "practice" for the fire forming, yeah yeah, still annoying. Being able to just buy 6cm brass from a good supplier is what keeps repeating in my head each time I wonder about 243AI.

If starting from from scratch, sure the 6CM wins. I wasn't, therefore the 243 AI won. What is it that actually sucks about fire forming? Losing a piece of fire formed brass does suck, aside from that what?

 

[pods8 (Rugged Stitching)]

If starting from from scratch, sure the 6CM wins. I wasn't, therefore the 243 AI won. What is it that actually sucks about fire forming? Losing a piece of fire formed brass does suck, aside from that what?

I have a 280AI and got it when nosler was the only one making brass so I made my own which was my fireforming experience background. Issues I had was it burned up components and barrel life on a temporary load. Yes you can dial in a load and practice with it but its not nearly as efficient. My major gripe just has to do with the fact I can't readily shoot without travel/time involved and if you need more brass on short notice that can suck. I made a mistake with a new lot of powder in some softer brass and lost all my primer pockets on that batch of brass while hunting, I didn't realize it till I went to load more rounds for another hunt and had to do an emergency trip to just form more brass. Yes that was my error and poor planning. It just isn't something one has to deal with if there is good formed brass already available.

Not bagging on the 243AI, I just wouldn't want one with 6CM component availability.

 

[AZ_Hunter]

Ok, so what is the consensus on what’s needed for the 243AI tikka:

Long action bolt bolt stop and m+ mags?

Thanks

 

[sveltri]

Ok, so what is the consensus on what’s needed for the 243AI tikka:

Long action bolt bolt stop and m+ mags?

Thanks

Just the M+ mags

 

[AZ_Hunter]

Just the M+ mags

Well hell. That’s easy….

Looks like a 243AI is in my future.

 

[HighUintas]

Well hell. That’s easy….

Looks like a 243AI is in my future.

Make sure your dies match up to the reamer used. Apparently the 243 AI chamber reamer has a couple different versions as well as dies. Getting the wrong set of dies could result in the shoulder diameter being sized 0.005 too much.

 

[AZ_Hunter]

Is the throat in the factory 243 1/8 long enough to use the heavy for caliber match bullets loaded to shoulder/boat tail junction with m+ mags?

 

[sveltri]

Is the throat in the factory 243 1/8 long enough to use the heavy for caliber match bullets loaded to shoulder/boat tail junction with m+ mags?

Are you talking about the factory standard chamber? I'm not sure I didn't check when I got my gun. You can load up a dummy round and send it with the gun to the gunsmith and he can chamber/throat it however you like. My loaded round with the 108 comes out at approx. 2.9"

 

[AZ_Hunter]

Are you talking about the factory standard chamber? I'm not sure I didn't check when I got my gun. You can load up a dummy round and send it with the gun to the gunsmith and he can chamber/throat it however you like. My loaded round with the 108 comes out at approx. 2.9"

Yes, what I meant was the chamber as is, non-AI.

 

[eric1115]

Is the throat in the factory 243 1/8 long enough to use the heavy for caliber match bullets loaded to shoulder/boat tail junction with m+ mags?

I did some measuring with mine before sending off for an AI chamber.

From the factory,
108 ELDM seated at the lands is 2.830 OAL in mine.
106 TAP is 2.885 OAL.

Both these seat the boattail junction below the neck/shoulder by ~0.050, so not terrible.

The M+ magazine (6.5 CM) allows a 2.95 OAL, factory M magazine that comes with .308 based chamberings are limited to 2.80. Both work with the standard short action bolt stop.

 

[Cahunter805]

I have been down the 243AI route and went back to the regular 243win. I used a 243win match reamer long throated and it pushed a 105VLD at 3080.
As far a fire forming I used the cream of wheat/pistol powder method and had good results.

 

[HighUintas]

I have been down the 243AI route and went back to the regular 243win. I used a 243win match reamer long throated and it pushed a 105VLD at 3080.
As far a fire forming I used the cream of wheat/pistol powder method and had good results.

What was the reason for switching back?

 

[AZ_Hunter]

I did some measuring with mine before sending off for an AI chamber.

From the factory,
108 ELDM seated at the lands is 2.830 OAL in mine.
106 TAP is 2.885 OAL.

Both these seat the boattail junction below the neck/shoulder by ~0.050, so not terrible.

The M+ magazine (6.5 CM) allows a 2.95 OAL, factory M magazine that comes with .308 based chamberings are limited to 2.80. Both work with the standard short action bolt stop.

That’s great info, thank you.

So another option, is to simply throat the factory barrel to allow 2.9ish COAL and use m+ mags.