284 Winchester build

[Gila]

This build started out with a Tikka T3 action that I had on another rifle. The action is 20 years old and one of the first Tikka T3 actions that were first produced in 2003. The barrel made by McGowen Precision Barrels, has a custom barrel profile and custom chamber that I had optimized to shoot a 162 gr ELD-X. The face of the action was squared up and hand lapped by McGowen's gunsmith (John Disney) before he twisted on the custom barrel.

I went with Mountain Tactical bottom metal and the standard length Tikka magazine. There was noticeable wear on the back of the action rails. I replaced the plastic bolt shroud with the metal "third lug" bolt shroud by Mountain Tactical to reduce further wear. I also replaced the aluminum recoil lug with the T3X steel lug. I went with the Limbsaver standard recoil pad. I also went with the Mountain Tactical RAD brake. It is more of a directional brake than a radial brake. The brake has no ports on the bottom thus no crap is blown around when shooting prone. In addition, the ports are angled to direct the blast somewhat away from the shooter. The brake shoots well and is what it is advertised to be. I like it.

There is no factory ammo available at present for the 284 Winchester. I loaded up some mild loads to break in the barrel. The barrel vibrations changed and the fouling reduced somewhat at round 15. I then started a ladder test of 5 rounds to work up a load. The fifth round gave me 2,900 fps and no pressure signs at all. I put up a target at 100 yds and shot a five round group. The first 3 shots came in at .4". All 5 shots were at 1". A total of 10 rounds and I am done working up that load!

The barrel is as accurate as I had hoped it would be. The entire build went together very well. The custom barrel profile fit the stock perfectly. I didn't need to modify the barrel channel at all. The total weight with scope is 9lbs. The parts list:

--- Tikka T3 action
--- McGowen Precision Barrel
--- Mountain Tactical bolt shroud, muzzle brake and bottom metal
--- Ember stock from J&A Outdoors
--- Tikka T3x long action magazines
--- Nikon tactical scope: 4x16 50mm with MOA reticle
--- Burris rings for the Tikka dovetail
--- Limbsaver Standard model recoil pad

 

[Tullis94]

The barrel has 284 win GAP stamped on the side. That is the same reamer mcgowen used on my barrel. What brass are you using? Will you do me a favor? Take a fired piece of brass and stick a bullet in the case without resizing. Is it a tight fit or does it have some room? Mcgowen told me their 284 GAP reamer was a no neck turn chamber. Mine is definitely not. I had to neck turn my brass. Awesome rifle! I love my 284 Tikka!

 

[Gila]

I specified a no neck turn as well. I just tried and can push a bullet through with little resistance. I sent in 3 dummy rounds and the free bore is exactly what I need it to be. Lupua brass.

 

[Tullis94]

I specified a no neck turn as well. I just tried and can push a bullet through with little resistance. I sent in 3 dummy rounds and the free bore is exactly what I need it to be. Lupua brass.

I could be wrong, but my understanding is that there should be zero resistance from a bullet in a fired piece of brass. About 4 or 5 thou total, for 2-2.5 thou all around the bullet. The bullet should drop right in. I don't want to burst your bubble, and I could be making assumptions, but I think Mcgowen simply used their 284 Win GAP reamer listed on their site. I don't see why they would stamp that on the barrel otherwise.

 

[Qholum37]

Nice build! Do you happen to know the diameter at the muzzle where it meets the brake? I have been thinking about getting this brake for my 6.5 PRC but I think it could also work pretty well on my dads 7 PRC. The muzzle diameter on both of these rifles is about .725" and its been kind of hard to find a good looking self timing brake that goes well with the smaller muzzle diameters. This one looks good!

Also, what is your COAL with the 162 and how far off the lands?? I've been getting the itch to do a 284 soon. Seems to be a perfect match for the Tikka action!

 

[Gila]

I measured the outside diameter of a couple with the Mit. 317

Nice build! Do you happen to know the diameter at the muzzle where it meets the brake? I have been thinking about getting this brake for my 6.5 PRC but I think it could also work pretty well on my dads 7 PRC. The muzzle diameter on both of these rifles is about .725" and its been kind of hard to find a good looking self timing brake that goes well with the smaller muzzle diameters. This one looks good!

Also, what is your COAL with the 162 and how far off the lands?? I've been getting the itch to do a 284 soon. Seems to be a perfect match for the Tikka action!

730 is my muzzle diameter. I think MT might have one for the 6.5 so it should fit even better. The COAL with the 162 ELD-x is 3.07”. Jam is 2.420”. I am running a CBTO of 2.405 which is 15 off the lands.

 

[Tullis94]

Same neck diameter as mine. Mcgowen lied to us both. That might be okay with necked up 6.5x284 brass but with straight .284 lapua brass .317 is not big enough. A loaded round will be about .315. The neck diameter needs to be a minimum of .319 and I would prefer .320-.321

 

[Gila]

I could be wrong, but my understanding is that there should be zero resistance from a bullet in a fired piece of brass. About 4 or 5 thou total, for 2-2.5 thou all around the bullet. The bullet should drop right in. I don't want to burst your bubble, and I could be making assumptions, but I think Mcgowen simply used their 284 Win GAP reamer listed on their site. I don't see why they would stamp that on the barrel otherwise.

I believe that of the two different reamers you can select, one is a straight SAAMI spec chamber for the short action 284 win. The 284 win GAP is a custom finish reamer. When I sent their gunsmith dept my action for the re-barrel; I also sent three dummy rounds and instructions for what I wanted. I sent Dan a copy of those instructions along with the tracking number for the package. I did’t send specs for the throat or the neck size but I did request a no-turn neck. The barrel came back with a throat that exactly matched my dummy rounds which used Lapua brass. Like I stated, I wanted to optimize the chamber for the 162 gr ELD-X. The barrel I ordered from McGowen is not a prefit. It is a custom barrel with a custom profile.

With all of my brass, new or fired, I run the expander through the neck. Too many times I have stepped on spent brass before I found it. And then I have opened a new box of brass only to find a caved in neck on top of the pile. Haven’t seen that with Lapua brass yet, however the expander has hit on some necks. From what I can determine, a neck turn chamber is .315. A no-neck turn chamber is .317-.318. So far I have had zero problems firing the brass. I haven’t seen any premature pressure spikes. No problems chambering a round or extracting. Obviously the first group was tight enough. What issues are you having that require you to turn the necks?

 

[Tullis94]

I believe that of the two different reamers you can select, one is a straight SAAMI spec chamber for the short action 284 win. The 284 win GAP is a custom finish reamer. When I sent their gunsmith dept my action for the re-barrel; I also sent three dummy rounds and instructions for what I wanted. I sent Dan a copy of those instructions along with the tracking number for the package. I did’t send specs for the throat or the neck size but I did request a no-turn neck. The barrel came back with a throat that exactly matched my dummy rounds which used Lapua brass. Like I stated, I wanted to optimize the chamber for the 162 gr ELD-X. The barrel I ordered from McGowen is not a prefit. It is a custom barrel with a custom profile.

With all of my brass, new or fired, I run the expander through the neck. Too many times I have stepped on spent brass before I found it. And then I have opened a new box of brass only to find a caved in neck on top of the pile. Haven’t seen that with Lapua brass yet, however the expander has hit on some necks. From what I can determine, a neck turn chamber is .315. A no-neck turn chamber is .317-.318. So far I have had zero problems firing the brass. I haven’t seen any premature pressure spikes. No problems chambering a round or extracting. Obviously the first group was tight enough. What issues are you having that require you to turn the necks?

Hey, if you are happy and not having issues then by all means keep it up I'm going to send you a DM for a link from another site. If you ever do have issues it might be worth checking out for you. Hopefully you never do! We might not agree on everything regarding your barrel being "custom" and not just a prefit but If the accuracy is satisfactory then what does it really matter!

 

[Gila]

SAAMI specs have quite a bit of “slop” in the dimensions because just about any type of brass you can think of is in factory ammunition. This is a drawing for the 7 PRC chamber. However, the dimension for the neck size is the same for all of the other 7mm (284) cartridges.

https://saami.org/wp-content/uploads/2022/06/Public-Introduction-7mm-Precision-Rifle-Cartridge-2022-06-16-rev1.pdf

 

[Gila]

Sighted the rifle in this morning. I have about 60 rds through it now. The holes touch at 200 yds when I do my part. This load really rocks!

Name: 162 sight 100
Notes: Imported from Chronograph, String 1 on 7/18/23, 9:33 AM
Shots: 10
Average: 2888 ft/s
SD: 6 ft/s
Min: 2879 ft/s
Max: 2898 ft/s
Spread: 19 ft/s
Power Factor Average: 468
Power Factor Low: 466
Power Factor High: 469
Temperature: 84
Weight: 162 gr.

 

[Gila]

I have run ballistics on the above load and have culled out my hunting ammo to be as consistent as possible. I have one more range trip to make before I start hunting. I am going to get some dope out at 500 yards to calibrate the profile in my rangefinder. Then it is practice holds at various ranges from different positions primarily using my pack and tri-pod. I did a comparison with Hornady Precision Hunter ammo in 280AI using the same bullet. I am sure there are better ways to compare the ballistic data but this is what I have for now. Thought I would share the data for those who may be interested:

The 280 AI:



My 284 Winchester Load:

 

[bigsky_hunter]

Nice build. What barrel length and contour did you go with? Did you have to modify the ember stock at all? Thanks

 

[mrh1958]

Sharp rifle !

 

[Gila]

Nice build. What barrel length and contour did you go with? Did you have to modify the ember stock at all? Thanks

I tried to duplicate the Tikka Roughtec Ember Contour as much as I could. Had help from a couple of Roksliders who took some measurements of their Roughtec barrels. I did a drawing and submitted it to the barrel maker. Turned out to be a perfect fit for the Roughtec Ember stock. The barrel is 24”.

 

[Packmansion]

A little late to the party. Was researching 284 win tikka. I am thinking about doing something similar. With the high bc why go with a magnum like 7PRC. My thought is take advantage of the BC. The build is incredible!

 

[Gila]

Since then Peterson started delivering brass. Lapua brass seldom comes and goes. The 284 win has been the mainstay for F-Class over the years so brass will be available. Also since then Stocky’s carbon VG stock for the Tikka has been on sale, so I have one on order for the 284 Win. I would get the Redding dies.