Optimal twist rate for 40 gr. bullets?

[204Shooter]

I think it is a generally accepted conclusion that Ruger went with a marginal twist rate for the 40 grain bullets when they decided to use a 1/12" twist. For all you experts out there, if you were to design your dream .204 and could pick your twist rate, what would you choose? 1/9", 1/10" or 1/11" twist? Would barrel length make a difference in your decision?

What do you think?

Note: I just read this thread and it looks like a 1/10" would be good???

[Neil S.]

I am far from an expert, but I do have first hand experience with stability problems with a 1 in 12 twist. I am also very interested in this issue of twist rate as I originally wanted to shoot the 39/40 grain pills in my gun. I know RIO has had great success with his 1 in 11 twist which is what I have been leaning towards as a replacement tube. I have no desire to shoot the 50-55 grain Bergers so I don't want a faster twist than I need.

-Neil

[Lenard]

I have a 1-10 with a 20 TAC and it shoots 40 vmax very well. Haven't had the weather to fine tune the load but shoots about 1/2 with a random load. I bought a PacNor barrel and had it put on my action. Very happy with how it shoots. I see an advantage for the 204 using a 45 gr. bullet with a 1-10 as it should stabilize very easily.

[Silverfox]

My Savage 12VLP in .204 Ruger with a 1 in 12 twist shot the 40 gr. Berger LTBs OK (I don't think they make them any longer), but the 40 gr. V-Max were all over the paper. I could not find a load for them, so I moved on to the 39 gr. Sierra BlitzKings.

I think to be safe, if you want to shoot 40 gr. bullets you should go with at least a 1 in 11" twist. That is the twist I have on a Savage 12VLP in .204 Ruger with a Pac-Nor super match grade barrel. It shoots the 40 gr. V-Max into nice little groups. I shoots the 39 gr. Sierras even better, but I have about 1,200 of the 40 gr. V-Max I need to shoot before I switch back to the 39 gr. Sierras.

[ryutzy]

1:11 will be probably be my next barrel. 1:10 would be my next choice. I am also a big fan of the 24" barrel for the 204. If using a shorter barrel (20 in) I would go with the 1:10 twist.

[Ray P]

I'll put in my .02 Back in 2006 I ordered a 20cal Hart barrel in sendero contour 26" finished length and all Hart offered was 1 in 12. I order a second Hart barrel a year later for another 204 project again all Hart offered was 1 in 12. I purchased a Ruger #1 in the varmint series it has a factory 26" 1 in 12 barrel. All rifles are shooter and a 5 shot group.250 or less is not hard to do. I'm using 40 Hornady, 40 Bergers, 35 Berger or 39 Sierras.
There might be an optimum twist as Rick has found out. Maybe I just got lucky on the 3 rifles I have??
Later
Ray P >
PS on side note how close are tolerances on barrel twist. Some barrel makers today a allow the customer to spec twist in 1/4 increments.

[futuretrades]

My howa has a 1 in 12 twist factory barrel. It will shoot 32 Vmax just under 1/2 " all day. Also shoots 39 SBKs even better, around 3/8". The only load I found for 40 Vmax is over H4895. Originally I tried H335 with the 40Vmax, but could not find the sweet spot, was around 1".

[Bitman]

My Cooper MVT, in .223, has a 1-14 twist.
It will shoot 40 grain Nosler BT into one hole at 50 yds.
And under 1/2" at 100 yds.
Would probably due 1 hole at 100 yds, if I would do my part.

[OldTurtle]

My AR has a custom cut chamber, to reduce the jump to the lands, with a 1/12 twist and it shoots the 39gr and 40gr bullets very well... When I tried the 45gr Hornady rounds, the group opened up a little, but not too much for Predator hunting... but too much for shooting Varmints as longer distances...

[Rick in Oregon]

Okay, I'll add my two cents.

After much thought and research to this very question, I opted for an 11 twist (Pac-Nor 3-Groove SS Super Match @ 24" w/custom chamber) and have never looked back. The rifle shoots any 40gr or the 39 SBK into one hole if the nut behind the rifle is in tune.

I believe that having the minimum twist required to stabilize the subject bullet is the way to go, as faster twists create more torque to add to recoil, are harder on bullet jackets, and limit the amount of actual velocity available due to jacket thickness.

Even the 40gr V-Max shoots well in my 11 twist, although it's not my bullet of choice:



The Sierra 39gr BK shoots even better, and is my "go-to" bullet for extended ranges, even in my 12 twist 204's. My Cooper M21 MTV in 204 is the standard 12 twist, and thrives on the 39SBK. The target below was looking good after five shots, about .3", but I wanted to shoot up the available ammo I had for a good chrono average, so continued to shoot a ten shot group using the 39SBK. Even with the wind acting up and me tired after much shooting, the group still stayed around a half inch. (It also illustrates that I'm no BR shooter!)



In the end, if given a choice as to the twist in a 204 Ruger, I'll take the 11 twist and run.

[Fred_C_Dobbs]

The 40-gr bullets all have very slightly different designs that will affect stability. Unless you intend to go overboard (and get, say, a 1:9 even though you believe a 1:10 will suffice), the most practical solution is to follow the manufacturers' recommendations. Some publish the numbers and the rest will provide it if you ask. If you don't have a particular bullet in mind, look up the data for all the candidate bullets and get a twist to match the fastest among them.