Thompson Center Encore in .300 Win. Mag.--Shooting Small Groups

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I have a Thompson Center Encore that I got a .300 Win Mag. bbl for. Its a breach loader single shot of course. I've been trying to develop an optimum load using Sierra Gameking #2125 150 gr bullets. It will shoot 100 yard groups of 1.5 MOA just fine, and I have gotten a few .75 MOA groups out of it.
I'm still doing load development using Accurate Magpro, and Quickload using the Chris Long tables for optimal bbl. time, taking velocities with my Chrono, and backing into an actual history matched Burn rate for the powder. I'm getting close to trying everything I can think of to make it shoot 1 MOA or better every outing. I just cleaned the crap out of the bbl, its a 28 incher by the way, stainless. It had maybe 400 rounds and I thought I was doing a good job of cleaning it, but I got a borescope and discovered a heck of a lot of copper in it. So, now it shiny and I'm getting it refouled a little to get some equilibrium back. The things I am doing now are neck turning all my Peterson cases, and I plan to start working on bullet seating depth too.
I have been just using 3.34 COAL as I worked on which powder to use. I tried, 4350, N560, RS Magnum, and Accurate Magpro. I want to achieve at least 3250 MV with the 150 gr. Sierra's. I can go to 3375 or so safely with this bullet and the AC Magpro, but no need to get that kind of velocity.

My question is this......am I just stacking deck chairs on the Titanic or with all my efforts is there any hope of this rifle ever shooting 1 MOA or better consistently? My next step is to try getting the bullet .02 to 03 of the lands, as I think 3.34 may be more like .07 off. Only I can't find any .300 Win mag modified cases for the Hornady LNL tool, so I'm sort of guesstimating based on trial and error no science exactly where I am. I can't believe you can't even find simple bushings, and modified drilled cases these days.........Good grief its crazy or there is a conspiracy.......I vascillate day to day on which it is......

Anyway, advice on what's achievable with this rifle? Its got 8 to 16 power Bushnell optics, and I've had no issue with scope on it.
 
Encores are capable of good accuracy but they are unique in some ways that can drive you nuts. The forearm MUST be isolated from the barrel and there are all sorts of avenues to go down for that fix. Simplest fix that works for me is to cut a 20 ga hull about 1/2" off the top (clean and no defects), slice in half, punch a hole in middle of each half that will allow the forearm screw to go through. Attach forearm using the halves such they are between the barrel and the forearm. Sounds crazy but it helps isolate the forearm. Second, make sure you are placing the forearm on the bag EXACTLY the same place each time. The difference in groups is likely different pressure points on the forearm. If you haven't done a trigger job, do it immediately, the Encore has one of the heaviest triggers on the planet. You can buy the replacement springs from Mike Bellm - LINK: Bellm Trigger Springs

It is not difficult to replace the springs at all and you can get a 2.5 trigger pull if you want one that low. I also recommend changing out the Hammer spring to a heavier one. No different that changing bolt action firing pin spring. In a hammer rifle, this is only way to speed up lock time. While at it, replace firing pin with heavy duty one.

Hope this helps.
 
I too (owned) a TC Encore with a 300 WM barrel, I did the piller bedded forearm, trigger spring & over sized action pin. My rifle would shoot 1/2 MOA at 200 yds, sometimes. It did all depend on consistent pressure on the forearm. Shooting with bags or bipods was very difficult to do and to consistently shoot tight groups. I finally gave up on it, sold it & moved on. I used h1000 & berger 215. With a 28 in barrel I ended up right at 3000 fps
 
I got a encore thanks to my lovely wife, mine is a 7mm Rem mag. I've had no issues with accuracy with mine. Shot off bipod and sand bags. It does have a Stratton hanger bar I added. It tightened it up slightly but with H1000 and 162 Eldx it has given me good repeatable groups. Just ordered a picatinny rail so I can mount a lil better optic for longer range shooting.
 

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Encores are capable of good accuracy but they are unique in some ways that can drive you nuts. The forearm MUST be isolated from the barrel and there are all sorts of avenues to go down for that fix. Simplest fix that works for me is to cut a 20 ga hull about 1/2" off the top (clean and no defects), slice in half, punch a hole in middle of each half that will allow the forearm screw to go through. Attach forearm using the halves such they are between the barrel and the forearm. Sounds crazy but it helps isolate the forearm. Second, make sure you are placing the forearm on the bag EXACTLY the same place each time. The difference in groups is likely different pressure points on the forearm. If you haven't done a trigger job, do it immediately, the Encore has one of the heaviest triggers on the planet. You can buy the replacement springs from Mike Bellm - LINK: Bellm Trigger Springs

It is not difficult to replace the springs at all and you can get a 2.5 trigger pull if you want one that low. I also recommend changing out the Hammer spring to a heavier one. No different that changing bolt action firing pin spring. In a hammer rifle, this is only way to speed up lock time. While at it, replace firing pin with heavy duty one.

Hope this helps.
Yep, it would be hard to bed the barrel since this is a rifle where you change barrels all the time, but your idea of a shotshell harmonic vibration dampner sounds interesting. I will try that, and yes I could change triggers, and some springs. Thank you for your ideas.
 
The Stratton hanger bar is probably the best way to isolate the firearm plus it gives yhe firearm added strength that allows you to use a bipod. If you try using a bipod off a standard forearm on a high recoil cartridge, the forearm screws will likely shear off. Yes personal experience. I would recommend if you are trying to go LR with it to eliminate the forearm isolation and to be able to use a bipod.
 
I had a 7mm Rem Mag that shot bug holes but to get that done I had to change the head space. I believe it had to be .003". When it was tighter or greater than that the groups would get larger.
 
These guns can shoot, but require work. Make sure the hinge pin is tight and measure your throat. Mine was super long. Being a break action, you can load any length you want. Check the crown as well.
My 300 likes 200 AB and very high doses of H1000.
 
I have a Thompson Center Encore that I got a .300 Win Mag. bbl for. Its a breach loader single shot of course. I've been trying to develop an optimum load using Sierra Gameking #2125 150 gr bullets. It will shoot 100 yard groups of 1.5 MOA just fine, and I have gotten a few .75 MOA groups out of it.
I'm still doing load development using Accurate Magpro, and Quickload using the Chris Long tables for optimal bbl. time, taking velocities with my Chrono, and backing into an actual history matched Burn rate for the powder. I'm getting close to trying everything I can think of to make it shoot 1 MOA or better every outing. I just cleaned the crap out of the bbl, its a 28 incher by the way, stainless. It had maybe 400 rounds and I thought I was doing a good job of cleaning it, but I got a borescope and discovered a heck of a lot of copper in it. So, now it shiny and I'm getting it refouled a little to get some equilibrium back. The things I am doing now are neck turning all my Peterson cases, and I plan to start working on bullet seating depth too.
I have been just using 3.34 COAL as I worked on which powder to use. I tried, 4350, N560, RS Magnum, and Accurate Magpro. I want to achieve at least 3250 MV with the 150 gr. Sierra's. I can go to 3375 or so safely with this bullet and the AC Magpro, but no need to get that kind of velocity.

My question is this......am I just stacking deck chairs on the Titanic or with all my efforts is there any hope of this rifle ever shooting 1 MOA or better consistently? My next step is to try getting the bullet .02 to 03 of the lands, as I think 3.34 may be more like .07 off. Only I can't find any .300 Win mag modified cases for the Hornady LNL tool, so I'm sort of guesstimating based on trial and error no science exactly where I am. I can't believe you can't even find simple bushings, and modified drilled cases these days.........Good grief its crazy or there is a conspiracy.......I vascillate day to day on which it is......

Anyway, advice on what's achievable with this rifle? Its got 8 to 16 power Bushnell optics, and I've had no issue with scope on it.
Hornady will drill and tap your fire-formed case for their comparator for $15...just had one done for my 300 WM using a fire-formed Petersen case...
 
I've had two Encore barrels, one in 338-06 and the other in 7mm RemMag, both rifles shot MOA consistantly once I developed a load for the rifle. I always torqued the forearm screws when I put the rifle together; however, I really like Muddyboots recommendation about the shotgun sell shim. Also the recommendation on the trigger job will make a huge difference in performance. Mike Belm puts a great trigger kit together and not very expensive at all. Good luck with the rifle.
 
I have a Thompson Center Encore that I got a .300 Win Mag. bbl for. Its a breach loader single shot of course. I've been trying to develop an optimum load using Sierra Gameking #2125 150 gr bullets. It will shoot 100 yard groups of 1.5 MOA just fine, and I have gotten a few .75 MOA groups out of it.
I'm still doing load development using Accurate Magpro, and Quickload using the Chris Long tables for optimal bbl. time, taking velocities with my Chrono, and backing into an actual history matched Burn rate for the powder. I'm getting close to trying everything I can think of to make it shoot 1 MOA or better every outing. I just cleaned the crap out of the bbl, its a 28 incher by the way, stainless. It had maybe 400 rounds and I thought I was doing a good job of cleaning it, but I got a borescope and discovered a heck of a lot of copper in it. So, now it shiny and I'm getting it refouled a little to get some equilibrium back. The things I am doing now are neck turning all my Peterson cases, and I plan to start working on bullet seating depth too.
I have been just using 3.34 COAL as I worked on which powder to use. I tried, 4350, N560, RS Magnum, and Accurate Magpro. I want to achieve at least 3250 MV with the 150 gr. Sierra's. I can go to 3375 or so safely with this bullet and the AC Magpro, but no need to get that kind of velocity.

My question is this......am I just stacking deck chairs on the Titanic or with all my efforts is there any hope of this rifle ever shooting 1 MOA or better consistently? My next step is to try getting the bullet .02 to 03 of the lands, as I think 3.34 may be more like .07 off. Only I can't find any .300 Win mag modified cases for the Hornady LNL tool, so I'm sort of guesstimating based on trial and error no science exactly where I am. I can't believe you can't even find simple bushings, and modified drilled cases these days.........Good grief its crazy or there is a conspiracy.......I vascillate day to day on which it is......

Anyway, advice on what's achievable with this rifle? Its got 8 to 16 power Bushnell optics, and I've had no issue with scope on it.
I had the same issues with mine, T/C Encore, the two quickest fixes were ordering a tight barrel hinge pin and a heavier HD locking bolt spring. Headspace is/can also be an issue. Headspace can be easily checked with a feeler gauge set. All these parts can be had at bellmtcs.com.
There also seemed to be an issue with some of the 28" Prohunter barrels, run a cleaning jag as you normally would and if you feel a loose spot / area around the 20-22" area, there was a quality issue and the result was diminished accuracy.
PM me if you have any questions, the website has many FAQs and tutorials. Good luck!
 
I got a encore thanks to my lovely wife, mine is a 7mm Rem mag. I've had no issues with accuracy with mine. Shot off bipod and sand bags. It does have a Stratton hanger bar I added. It tightened it up slightly but with H1000 and 162 Eldx it has given me good repeatable groups. Just ordered a picatinny rail so I can mount a lil better optic for longer range shooting.
I looked at the Stratton hanger bar site, and this also looks interesting. I never heard of a hanger bar before. I may try the shotgun shell dampner first, and then go there next. Thanks for this too.
 
+1 on the locking bolt spring. The 12 Ga locking bolt spring will tighten this up immediately! They were available at one time from TC. They are easy to change if you use a ratchet style wood clamp. The clamp will retract the locking bolts, hold them in place while you knock out the holding pin. Just reverse procedure to put new spring in.
 
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