Which 7mm in a Tikka

[Gonewest]

I want a new rifle. Currently, I have a 6.5 Sherman that I built on a Savage action and a .270 Browning A-bolt. I mainly use the Sherman but it’s almost 14lbs fully loaded. I have an opportunity to but a .243 Tikka to use as a donor. I’d convert it to a long action. I want a 7mm and shoot 160-175 grain bullets. I was originally going to go with a .280AI. The the 7PRC came out and was debating between those two. I do have some concerns about the length of the Tikka mags. So I started looking at the 7SAUM and .284 Win. I know others have gone done this road and I’m looking for opinions. I’d prefer not to have to purchase a different bolt unless I’m able to sell the standard one.

Some requirements for this gun
- be capable at 600 yards for hunting
- max barrel length 24” but prefer 22” maybe 20”
- be able to add a suppressor in the future
- 8-8.5 lbs will a scope

 

[eLightfoot]

If the donor is a .473 bolt then the .284 is a no brainer

 

[Tahoe1305]

280 AI should outrun the 284 but may also leave you limited on OAL. 284 shouldn’t have mag length issues. Also you can get 284 components today. Not positive that will be the case for a while with PRC. Just looked and Lapua 284 brass is in stock.

I’m building a 7wsm on a tikka currently. But only because I have all components from a 7wsm savage I built a few years back.

Good luck.

Edit: reading some other forum posts on the 284 in a LA. Folks reporting 2800+ fps with 168g bullets and 20” barrel. Appears to be loaded long and not positive if it’s a custom throat. But that’s solid performance from a short barrel. I’d switch from my 7wsm if i could get a prefit in that longer chamber.

 

[Gila]

If the donor is a .473 bolt then the .284 is a no brainer

The 284 Winchester shouldn’t lose much velocity in a 22 inch or a 20. I thought hard about it, but decided to go with 24” and a recessed crown. My primary loads will be 162 and 180 gr. The cartridge is definitely capable of cleanly harvesting elk and moose out to 1K with the right bullet. Just make sure you chamber with a match reamer (GAP) with no neck turn that has enough free bore to shoot the heavy LDFs. The OAL with a 180 VLD is about 3.2” There are some double base powders out there that are in the H4350 burn range that will pump up the velocity for the heavies. The 284 is supposed to be easy to tune.

The downside is that there isn’t really any factory ammo to speak of. Lapua or Peterson brass is the way to go. Suggest you jump on the brass as soon as you make a decision. I bought some Lapua brass the day I ordered the barrel and the next day all of the brass was gone. I am chomping on the bit to get my barrel and put it all together.

 

[swopie]

I want a new rifle. Currently, I have a 6.5 Sherman that I built on a Savage action and a .270 Browning A-bolt. I mainly use the Sherman but it’s almost 14lbs fully loaded. I have an opportunity to but a .243 Tikka to use as a donor. I’d convert it to a long action. I want a 7mm and shoot 160-175 grain bullets. I was originally going to go with a .280AI. The the 7PRC came out and was debating between those two. I do have some concerns about the length of the Tikka mags. So I started looking at the 7SAUM and .284 Win. I know others have gone done this road and I’m looking for opinions. I’d prefer not to have to purchase a different bolt unless I’m able to sell the standard one.

Some requirements for this gun
- be capable at 600 yards for hunting
- max barrel length 24” but prefer 22” maybe 20”
- be able to add a suppressor in the future
- 8-8.5 lbs will a scope

You can’t convert a short action to a long action.

 

[Gila]

You can’t convert a short action to a long action.

The tikka t3 is sort of a long action. Better classified as a standard length.....max cartridge overall length is 3.5”. The long action Tikka mags are limited to 3.37”. For short action cartridges, Tikka puts in a bolt stop to limit the throw of the bolt is all.

 

[PathFinder]

You can’t convert a short action to a long action.

Tikka actions are all the same sort of medium length. Converting a "short" action to a "long" action only requires swapping the bolt stop and magazines.


Sent from my Pixel 6 using Tapatalk

 

[WeiserBucks]

I'd do a 284 WIN in a heartbeat.

 

[Gonewest]

Edit: reading some other forum posts on the 284 in a LA. Folks reporting 2800+ fps with 168g bullets and 20” barrel. Appears to be loaded long and not positive if it’s a custom throat. But that’s solid performance from a short barrel. I’d switch from my 7wsm if i could get a prefit in that longer chamber.

I read some of the same info.

 

[Gonewest]

The 284 Winchester shouldn’t lose much velocity in a 22 inch or a 20. I thought hard about it, but decided to go with 24” and a recessed crown. My primary loads will be 162 and 180 gr. The cartridge is definitely capable of cleanly harvesting elk and moose out to 1K with the right bullet. Just make sure you chamber with a match reamer (GAP) with no neck turn that has enough free bore to shoot the heavy LDFs. The OAL with a 180 VLD is about 3.2” There are some double base powders out there that are in the H4350 burn range that will pump up the velocity for the heavies. The 284 is supposed to be easy to tune.

The downside is that there isn’t really any factory ammo to speak of. Lapua or Peterson brass is the way to go. Suggest you jump on the brass as soon as you make a decision. I bought some Lapua brass the day I ordered the barrel and the next day all of the brass was gone. I am chomping on the bit to get my barrel and put it all together.

When do you get your barrel? I’m interested in your results. Thanks for the tip on the reamer.

 

[Gonewest]

I'd do a 284 WIN in a heartbeat.

Any particular reason why?

 

[Tullis94]

I love the 284 win. In a tikka the 284 will match a 280ai simply because the 280ai is limited by mag length. With all that being said, you'll want to get brass for the 284 before you commit. Lapua quit making it and Peterson is rarely available it seems. My 24" barrel with 53.5 grain of H4350 and 162 eldms is right at 2925fps. My dads 25 inch barrel throated specifically for 180 eldms shoots 2830fps with H4831sc.

 

[WeiserBucks]

Any particular reason why?

Lapua brass, very accurate, fits perfectly in a Tikka and enough power for any game I'll ever hunt.

 

[Tullis94]

When do you get your barrel? I’m interested in your results. Thanks for the tip on the reamer.

Just a heads up the GAP reamer is NOT a no neck turn reamer. It has a .316 or .317 neck diameter. My loaded Lapua brass is .3155". After firing the brass a bullet will barely fit into the fired case but it is TIGHT! Dan at Mcgowen told me it was no neck turn but he was either wrong or lying.

 

[Tahoe1305]

Does anyone have the 284 OAL in a SAAMI reamer barrel with 162eldx?

Specifically a carbon 6 barrel if someone’s got one.

This thread makes me want a 284 over a 7wsm! But want to make sure a std reamer (that carbon 6 has) will allow for the longer bullets.

 

[eLightfoot]

A 284 case with long bullets is just perfect for the tikka long action mags. Plenty of room and they feed slick from factory mags. The 5 round mags will fit 4 284 rounds.

 

[Tullis94]

Does anyone have the 284 OAL in a SAAMI reamer barrel with 162eldx?

Specifically a carbon 6 barrel if someone’s got one.

This thread makes me want a 284 over a 7wsm! But want to make sure a std reamer (that carbon 6 has) will allow for the longer bullets.

Preferred barrels will throat to a dummy round for no extra cost. They sell carbon barrels also. I have nothing but good to say about Preferred.

 

[Tahoe1305]

Preferred barrels will throat to a dummy round for no extra cost. They sell carbon barrels also. I have nothing but good to say about Preferred.

Thx. Already got an order in with carbon 6. Can adjust likely but not cnx. Prefer to use SAAMI if I can. But will stick with wsm if it gets too complicated!

 

[Gila]

When do you get your barrel? I’m interested in your results. Thanks for the tip on the reamer.

I am hoping to get it 3-4 weeks from now. Here is the deal with the neck size: 284 win Lapua brass has a neck wall thickness of .015. Take that times 2 and add .284 for the bullet and you end up with a neck diameter of .314. To find the bushing size for your sizing die subtract .004 (3 for tension and 1 for spring back) for a bushing size of .310-.311. Once the case is fully resized, it goes into the neck expander die and the mandrel will push the neck tension out to .0025.

So the typical neck size for the chamber is a loose .316-.317. BUT....when you order your barrel you need to tell them you are using normal brass and not doing any neck turns on expanded cases. The reason why is because Lapua just recently started making .284 win brass. The PRS crowd was expanding 6.5 x 284 brass for the 284 win. With that much expansion the necks needed to be turned to make them concentric. The turned neck walls end up being thinner to be concentric but I don’t know by how much. So a standard neck size in the chamber is too loose for that particular brass.

EDIT: absolutely no crimp on the seating die....back it off completely.

 

[Tullis94]

I am hoping to get it 3-4 weeks from now. Here is the deal with the neck size: 284 win Lapua brass has a neck wall thickness of .015. Take that times 2 and add .284 for the bullet and you end up with a neck diameter of .314. To find the bushing size for your sizing die subtract .004 (3 for tension and 1 for spring back) for a bushing size of .310-.311. Once the case is fully resized, it goes into the neck expander die and the mandrel will push the neck tension out to .0025.

So the typical neck size for the chamber is a loose .316-.317. BUT....when you order your barrel you need to tell them you are using normal brass and not doing any neck turns on expanded cases. The reason why is because Lapua just recently started making .284 win brass. The PRS crowd was expanding 6.5 x 284 brass for the 284 win. With that much expansion the necks needed to be turned to make them concentric. The turned neck walls end up being thinner to be concentric but I don’t know by how much. So a standard neck size in the chamber is too loose for that particular brass.

EDIT: absolutely no crimp on the seating die....back it off completely.

My 284 win Lapua brass is .315-.3155 I really wish it was .314 because the GAP reamer used on my 284 requires me to neck turn.