Thompson Center Compass II Compact .223.

[Tex S]

16.5" bbl, 1-9 twist.

Bought my kid this rifle.

Put about 40 rounds of Winchester factory thru it before I started loading for it. Accuracy was poor... 2.5" groups.

I have been through about 100 handholds and I'm struggling to get this rifle to shoot sub moa.

The first 50 cases I loaded I tried 5 different bullets over smaller charges of H335.

Barnes 55gr ttsx. Shot 1.25"... .050" off
Barnes 62gr ttsx Shot 1.5"... .050 off
Sierra 55gr SBT Shot 1.4"... .010 off
Swift 62gr scirocco II Shot deplorable... 3+".. .010 off
Nosler 60gr partition Also shot bad... 2.5".. .010 off

The Barnes 55gr ttsx looks promising, and truth be told it was the bullet I wanted to use anyway. I started seating this bullet at .050 off and haven't tried any other seating depths.

Since none of the above loads proved to be ringers, I figured maybe the barrel just needed more rounds through it. So, I loaded up another 50 rounds using the same bullets as listed above. This time I used heavier charges of H335, and I was actually getting some decent velocity that I am happy with. The bullets grouped almost identical to the first 50, with the Barnes 55gr ttsx winning again.

So, I want to continue developing the 55gr ttsx load, but I have a few questions.

1) I have way to many powders on hand. Should I try the 55gr ttsx with a different powder and see if I can squeeze another 1/2" out of it? 25gr of H335 is giving me about 2975fps out of this short barrel. No overpressure signs.
2) Seating depth. Should I stick with the H335 and play with seating depths?

Any input would be appreciated!

[jetinteriorguy]

My suggestion, do one thing at a time. One powder, one bullet, and do a proper load workup. I prefer five shot groups, then when I find an accurate load I shoot four five shot groups to verify. Once I’ve verified I fine tune it by going down a tenth of a grain, and up a tenth of a grain. If it still maintains the same or better accuracy, I then play with seating depth to see if I can squeeze a little better group out of a load. It’s a slow time and component consuming way to do this but does work well for me.

[reynolds357]

Originally Posted by jetinteriorguy

My suggestion, do one thing at a time. One powder, one bullet, and do a proper load workup. I prefer five shot groups, then when I find an accurate load I shoot four five shot groups to verify. Once I’ve verified I fine tune it by going down a tenth of a grain, and up a tenth of a grain. If it still maintains the same or better accuracy, I then play with seating depth to see if I can squeeze a little better group out of a load. It’s a slow time and component consuming way to do this but does work well for me.

The Compass is a cheap looking rifle, but every one I have ever seen has been crazy accurate. Anything going on with Scope?
Quite a few of my scopes have made the warranty trip when compared to my control scope, a fixed 36 Weaver.

[Tex S]

I wondered about the scope, but after firing the second round of reloads I quit worrying since all the ammo printed the same groups as the previous testing.

[Shadow9mm]

Try a seating depth test. Try 5 to 6 groups with 0.003 difference in seating depth. I have cut groups in half using this method

[reynolds357]

Originally Posted by Shadow9mm

Try a seating depth test. Try 5 to 6 groups with 0.003 difference in seating depth. I have cut groups in half using this method

It can make a drastic difference. Play with seat depth. Find seat depth then play with powder charge. Then seat depth again.
The ladder test works.

I have found that when I find a bullet powder combo a rifle likes, it shoots at a wide range of powder charges and seat depths.
I built a .270 that will shoot most anything under 1.5 Moa. But it will shoot 130 Interlock over AA4350 sub 3/8 moa across a 5 grain charge range and anywhere from in the lands to backed off to the front of the cantelure.

[Shadow9mm]

One other though. check your action screws. friends compass in 308 was grouping 2in, and having problems. we re-torqued the action screws, now it shoots steel cased red army under 1moa.

[44 AMP]

16.5" bbl, 1-9 twist.

I'm struggling to get this rifle to shoot sub moa.

Other than the usual checks on the rifle (screws, bedding, scope, etc,) have you considered that the simple fact that the bullets you are using 55-62gr might not shoot sub MOA from a 1-9" twist?

Those same bullets and loads MIGHT run sub MOA in a gun with a 1-12" twist.

OR it could just be your individual barrel isn't up to the task. Lots of possibilities.

If possible, run some of the heavier (70gr+) slugs and see if they shoot any better.

As an example, I have a .22-250 that goes sub MOA with 52/3gr match bullets and 55gr SPs but only does about 2MOA shooting the Sierra 63gr semi spitzers. Heavier bullets are a complete waste of time in that gun, 1-14" twist.

The 1-9" is reported best with the heavier .22 slugs and usually "acceptable" with 55-62gr ball or equivalent. Acceptable might very well not be sub MOA.
I don't have one that fast, so can't speak from personal experience on that.

[reynolds357]

Originally Posted by 44 AMP

Other than the usual checks on the rifle (screws, bedding, scope, etc,) have you considered that the simple fact that the bullets you are using 55-62gr might not shoot sub MOA from a 1-9" twist?

Those same bullets and loads MIGHT run sub MOA in a gun with a 1-12" twist.

OR it could just be your individual barrel isn't up to the task. Lots of possibilities.

If possible, run some of the heavier (70gr+) slugs and see if they shoot any better.

As an example, I have a .22-250 that goes sub MOA with 52/3gr match bullets and 55gr SPs but only does about 2MOA shooting the Sierra 63gr semi spitzers. Heavier bullets are a complete waste of time in that gun, 1-14" twist.

The 1-9" is reported best with the heavier .22 slugs and usually "acceptable" with 55-62gr ball or equivalent. Acceptable might very well not be sub MOA.
I don't have one that fast, so can't speak from personal experience on that.

My AR with 1 in 7 twist will shoot 55 and 62 sub 1/3moa.
(White Oak barrel upper I custom built)

[Shadow9mm]

Originally Posted by 44 AMP

Other than the usual checks on the rifle (screws, bedding, scope, etc,) have you considered that the simple fact that the bullets you are using 55-62gr might not shoot sub MOA from a 1-9" twist?

Those same bullets and loads MIGHT run sub MOA in a gun with a 1-12" twist.

OR it could just be your individual barrel isn't up to the task. Lots of possibilities.

If possible, run some of the heavier (70gr+) slugs and see if they shoot any better.

As an example, I have a .22-250 that goes sub MOA with 52/3gr match bullets and 55gr SPs but only does about 2MOA shooting the Sierra 63gr semi spitzers. Heavier bullets are a complete waste of time in that gun, 1-14" twist.

The 1-9" is reported best with the heavier .22 slugs and usually "acceptable" with 55-62gr ball or equivalent. Acceptable might very well not be sub MOA.
I don't have one that fast, so can't speak from personal experience on that.

Scratching my head... I always understood 1:9 favored lighter bullets, not heavier.

https://www.nrablog.com/articles/201...r-ar15-barrel/

Image from above article.

[44 AMP]

Scratching my head... I always understood 1:9 favored lighter bullets, not heavier.

As the chart you posted shows, it does, but look what its compared with. FASTER twists.

What would the chart show if it also included the 1-12" or 1-14" twist the .223 started out with??

Also, not being very familiar with the Compass II, I looked it up, and its a "$400" budget rifle. Isn't expecting sub MOA from that a bit much??

[Shadow9mm]

Originally Posted by 44 AMP

As the chart you posted shows, it does, but look what its compared with. FASTER twists.

What would the chart show if it also included the 1-12" or 1-14" twist the .223 started out with??

Also, not being very familiar with the Compass II, I looked it up, and its a "$400" budget rifle. Isn't expecting sub MOA from that a bit much??

Surprisingly no. My friend compass in 308 will do sub moa with steel cased red army. Half moa with factory match. Mine in 30-06 was lackluster at about 1.25 to 1.5 with factory but is 0.67 with my hand loads. And they have a moa guarantee with match ammo.

As far as the slower twists go, my understanding is this. They used longer barrels giving higher velocity. The higher velocities increased rpm with the slower twist increasing stability. And they were intended to be marginally stable, so the fmj bullets would tumble and yaw better upon striking a target. But the twist rate was increased due to instability issues as well as shortening of the barrels.

The article i linked above says about the same, saying that if you want a 1:12 you should stick with a 20in barrel and 55g or lighter bullets.

So yes the chart is primarily applicable to 16in barrels, but the OP has a 16.5in barrel in this case. Going to a 20 would change those ranges, you are correct.

[reynolds357]

Originally Posted by 44 AMP

As the chart you posted shows, it does, but look what its compared with. FASTER twists.

What would the chart show if it also included the 1-12" or 1-14" twist the .223 started out with??

Also, not being very familiar with the Compass II, I looked it up, and its a "$400" budget rifle. Isn't expecting sub MOA from that a bit much??

At one time, might still be so, the Compass had Sub Moa guarantee. I bought two for about $140 each. They both had Sub Moa stickers on them.

[44 AMP]

Ok, if the maker gives you a subMOA guarantee, that's a different matter, since they made the claim their product should deliver on it. With what ever ammo they used. With other ammo, look and see if that guarantee is still valid. Odds are, its not.

One sometimes finds budget grade rifles that shoot really well. But I wouldn't expect that as the norm, unless the maker guarantees it.

[Tex S]

Thanks for the replies, guys. Yes, according to TC this rifle is supposed to be sub moa.