Hodgon Tite Group

[dellet]

My experience is a little different with CFEBLK. For supersonic load testing I used 3 rifles (8.5" AR, 16" AR, and 18" bolt gun) and the results showed similar performance between H110/W296 and CFEBLK. However, H110 produced a little more speed, with CFEBLK struggling to achieve 1080fps range out of 8.5" SBR. Same 195gr projectile with 11.3gr CFEBLK shot through 8.5" barrel acheived 918fps. Whereas, shot through 18" barrel reached 1076fps. My load tests were done in mid-60F weather. CFEBLK provided good accuracy (3/4" group at 50 yards out of SBR), and it burned cleaner than H110 in all of my tests (no idea why the difference with Dellet on this one). I am running adjustable gas blocks in my guns so I can't speak to issues with excessive gas blowback.

As Dellet said... H110 is hard to beat for supersonics. For me the Vihtavuori N110 is my choice for subsonics out of my 18" bolt gun. Surprisingly, N110 can reach 1080fps for heavy subs out of 8.5" SBR, but just doesn't have the legs to achieve higher speeds for supersonic loads.

The problem with CFE is that it produces too low of pressure with subs, unless it is a long bullet and you can compress the powder. With out that it just does not produce enough pressure to blow the neck out and seal the chamber. It does not matter how tight you screw the adjustment down in the block, if the gas blows by the case.

One of the reasons it's popular is that it will cycle anything, but the reason it does that, is because it produces a tremendous amount of gas. Again that is do to low peak pressure. The side effect of low peak pressure is high muzzle pressure. High muzzle pressure produces more decibels to suppress out the barrel and a higher pop out the ejection port when the bolt opens, along with the gasses that blew past the case.

Another issue that comes up are extreme ES numbers, with a low density load, like many sub loads are, a triple digit ES is not all that uncommon. If your 3/4" at 50 yards is mostly vertical, you might want to look at that. There really is no reason not to have a 5 shot ragged hole at 50. An SBR with a decent barrel and 6X scope should be borderline MOA out to 200 yards with subs.

I am a bit of a powder snob when it comes to subsonic shooting. For the most part I use N120 for carbine gas or N105 for pistol. The only place I use 296 for subs is in a 10" carbine gassed upper.

The powders that are easy to tune for subs like 1680 and CFE provide reliability at the price of noise, gas and grime.

For supers it's a completely different discussion and that has to be broken down to above and below 150 grains of bullet weight.

It can get complex matching a powder to a bullet and barrel length if you want best performance. If you just want function and holes in paper or ringing steel sound, its pretty easy. The cartridge is fully capable of 1/2 MOA with supers and MOA +/- with subs at 2-300 yards. Most people just don't give it the time or effort.

 

[Oso]

Dellet - as always nice technical breakdown. Talked to me about N120 versus N110 for subsonic. Also, have you done any workup using the Lehigh Extreme Expansion 194gr subsonic bullets...I had some interesting results.

Thanks

 

[dellet]

N120 is a very nice powder, a bit slower than 1680, and a bit more bulk. So it takes a bit more powder to reach the same velocity, and has more bulk for weight. You end up with better case fill, so generally smaller ES numbers. Burns cleaner and quieter. The added bonus of copper fouling additives.

N110 is faster than 296/H110, so it depends how you use it. For subs it’s probably a toss up, for supers you max out pressure at a lower velocity. At lower case fills they can be a little unpredictable, but not terrible. 296 is about the fastest powder I can use in the 10” carbine gas, N110 just doesn’t quite have enough pressure at the port or enough dwell time for it to cycle.

When trying to use the same powder Sub/Super it’s tricky, they act completely different. I am very anti 1680 for subs. Loud, dirty lots of flash even out the end of a suppressor. Just too much powder left burning even in a 16” barrel. I’ve seen a first round fire ball out the end of a suppressor on a 24” barrel with a 10 grain load behind a 175 grain bullet as a sub. Put 20 grains under the same bullet, almost no flash from a 16”. Wipe the outside of the case, size and load. The sub load needs a week in stainless pins to come clean enough to size. You really would not know they are the same powder.

You really can manipulate the burn rate of powders through a fairly wide range and use it to your advantage.

The Lehigh 194 ME is a great bullet. I load that with either N105 or #9. Both will burn almost 100% in a 7” barrel.

There really is just too many bullets and powder combinations for the cartridge if you enjoy load work ups. The last bullet I spent any real time with was the Speer 150 Gold Dot in a 12” model 7. Just under 2200 fps and about 3/4” at 200 yards using Accurate’s 11FS. It’s a neat bullet.

Enough of a thread drift.