Super Fast Twist Barrels for Hammer Bullets

[QuietTexan]

In your experience: do solids require a different twist than jacketed bullets?

Absolutely unequivocally - yes, much faster. It's not only about stability (which you nailed with length/density) but it's coming to light that terminal ballistics can be drastically different when the bullet has more angular momentum on impact, and least in shedding petal designs.

It's been brought up here once already, but the Q 3-twist 8.6 BLK has been a new experience for me this year. I'm planning on using the Makers 350gn expanding sub this year, it looks like a mechanical broadhead on steroids and I'm fully expecting to remove the heart and most of the lungs of a whitetail through the ribs with it. With my luck will still run 150 yards

Maker bullets: 350 Grain 8.6 BLACKOUT Subsonic Expanding Bullets (Box Qty - 25) !!!! NOTE: KEEP UNDER 1000 FPS, EMAIL [email protected] IF OUT OF STOCK. DO NOT BACKORDER, YOU MUST EMAIL, Projectiles, 8.6350SUB

Maker 8.6 Blackout Subsonic 350g

The Maker REX bullets are precision CNC machined, lead free, solid copper expanding projectiles. REX projectiles expand to nearly 3 times the original diameter while maintaining nearly 100% of its original weight. Each REX projectile has been engineered to perform in a given velocity range to...

owloptics.nz

I still am a big proponent of the Partition/ A-Frame design for cup-and core hunting bullets. I was never into trying to get violent expansion from target bullets, my theory was I wanted to punch all the way through and leave a large permanent would channel that gushed. Hammer and CE monos offer me that performance with the shank, and add the petals shearing off.

Source:

8.6 Blackout, 338gr, Expanding | Firehole Arms

fireholearms.com

 

[tacomHQ]

I did some initial load work up yesterday with the 338 Edge and the 175 HH's in a 9 twist tube, I'm at 3700fps with no sign of pressure at all

Picture of the gun? Group data? Inquiring minds want to know...
Your numbers and other would indicate twist rate/stability and speed are on a predictable curve/line.
In some conditions speed is KING. Less wind call and less flight time.

 

[Zen Archery]

Cut barrel or button?

Button. 2015, BA barrel.

 

[ButterBean]

Picture of the gun? Group data? Inquiring minds want to know...
Your numbers and other would indicate twist rate/stability and speed are on a predictable curve/line.
In some conditions speed is KING. Less wind call and less flight time.

H4350 93g-97g
Groups were as per usual for Hammers, sub Moa.
Shooting with no brake so it kicked a tad

 

[tacomHQ]

View attachment 487889View attachment 487890

H4350 93g-97g
Groups were as per usual for Hammers, sub Moa.
Shooting with no brake so it kicked a tad

A "tad"... Terrible Angry Dinosaur. I would only watch...

 

[tacomHQ]

View attachment 487889View attachment 487890

H4350 93g-97g
Groups were as per usual for Hammers, sub Moa.
Shooting with no brake so it kicked a tad

Another advantage to "speed": SD errors show up later in the ballistic curve/range...

 

[waspocrew]

Another advantage to "speed": SD errors show up later in the ballistic curve/range...

I could be wrong, but he may have just been pressure testing and grabbing velocity at each charge of 93, 94, etc… hence the large ES.

 

[tacomHQ]

I could be wrong, but he may have just been pressure testing and grabbing velocity at each charge of 93, 94, etc…

Perhaps... my minor point is that applying the speed over your working distances can work toward your favor by reduced vertical error at the target. Along with "speed" for a given time period gravity is also king until the aerodynamics of the flying round starts to raise its ugly head. While I will instantly argue SD to ELR or anything most likely beyond 800 (normal parameters) on most shorter ranges of 2-400 SD's barely show up. Our reticle works on this principle. Kill zones and time. All bullets pass thru time at the same rate of vertical drop until the aerodynamic function starts adding percentages of variation- hopefully consistent.

 

[ButterBean]

I could be wrong, but he may have just been pressure testing and grabbing velocity at each charge of 93, 94, etc… hence the large ES.

Yes Sir yhiatcwas just a feeler for where I need to be, that was 5 shot each at 1 grain increments

 

[HARPERC]

A "tad"... Terrible Angry Dinosaur. I would only watch...

My friend @ButterBean has acquired a few nicknames over the years. My grandson, and I are stealing a line from the Virginian; "Smile when you call him that stranger"!

English being what it is I suppose you could have been talking about the rifle!

For those naming rifles TAD could be a good one.

 

[tacomHQ]

My friend @ButterBean has acquired a few nicknames over the years. My grandson, and I are stealing a line from the Virginian; "Smile when you call him that stranger"!

English being what it is I suppose you could have been talking about the rifle!

For those naming rifles TAD could be a good one.

One time I was sitting on the river in a Blown-V-Drive (modified tunnel hull) , parked, talking with other people when the Conservation Guys come tooling along. They anchor, get out onto the sand bar (about a foot deep) point at my boat and says "who owns that?". Not much I could say and I take claim. At which point he states "that boat looks loud" and proceeds to write me a ticket. Never even turned the key. Now mind this is an over the transom exhaust- with Aero mufflers... you could talk at normal tones at idle and minor cruise - WOT a bit different.
That gun just screams kicks like a "son of a gun" at those numbers- but I ain't no warden. So "no" not at the owner just the "TAD" fits the rifle- and he said it not me.

 

[HARPERC]

. So "no" not at the owner just the "TAD" fits the rifle- and he said it not me.

I knew that. Just an attempt to continue the humor.
Best Wishes!

 

[SheepShapeAK]

I just picked up a 1:7 twist for a SAAMI spec 7PRC.

My buddy has a reamer, so once I get it chambered I'll let you guys know what my load development finds out. ADG brass already inbound.

Need to grab some 177 HH to test, along with some other solids.

 

[JTH]

In your experience: do solids require a different twist than jacketed bullets?
Lower density= longer per weight... which would seem to indicate more twist requirement.
We have also seen conclusively: Barrel mfg A will stabilize bullet mfg 1 but not bullet mfg 2. Yet Barrel mfg B will stabilize Bullet mfg 2 but not stabilize Bullet mfg 1. One of the questions we ask is "what bullet" which leads to the barrel mfg recommendation.

That's right. If you want to shoot the heavy for caliber, higher BC bullets, solids will require more spin to stabilize due to their length. Lead is heavier than copper, so it takes a longer copper mono to get to the same weight as a jacketed lead bullet. Most of the solid mono manufacturers list a recommended barrel twist rate, stick with their advice or possibly even a little faster. Using a ballistic app, I'm plugging in all the data and looking for a minimum gyroscopic stability factor above 1.50, the higher the better for improved terminal performance, ideally closer to 2.0