assorted questions...if anyone can help

[richalexander97]

hi i've not been on the forum for a while, i had a few questions that have accumilated, if anyone has answers, thanks

1)has anyone shot a .17/19/20 practical (or similar .223 cased round), was the muzzle report noticably lower than a .223? not in terms of noise, but the percieved muzzle blast. for example would a 17 rem be closer to a 21 fireball in this regard.

2)are .17/19 barrels lighter? if you had a long barrel with a light profile, would it be much lighter than an equivalent 22 barrel?

3)has anyone played with a 6mm on a fireball case...did it offer much energy increase over 21 fireball?

4)ive heard that short fat cases are more efficient...how does this manifest itself ballistically...is it giving more propulsive efficiency, or more accuracy related

5)if one had a semi auto which was recoil operated (either by a moving barrel, or just the recoil of the round itself), would this allow for a lighter gun than the usual AR style action?

6)how well do suppresors reduce muzzle report/concussion with larger rounds, eg. grendel sized

7) for fast, 'point target shooting', are long-eye-relief optics generally better, eg. a 2x optic with a generous field of view, as opposed to the usual ACOG

8)and lastly....i noticed that 6mm-223 wildcats have a pretty high energy (similar to .224 valkyrie but way less powder).... does anyone know the approx powder capacity of these rounds, is it lower than .223 due to the longer bullet?

 

[Tommie]

Never did a side-by-side comparison but the 20 Practical seems to have more crack than a 223.

 

[L1986]

And a smaller caliber barrel will weigh more than a larger caliber of the same contour

 

[richalexander97]

And a smaller caliber barrel will weigh more than a larger caliber of the same contour

so your saying a 30cal barrel would weigh more than a 17....surely that cant be the case. although the M1 carbine was ultra light...i dont know how they achieved that...something like 2kg

 

[L1986]

No I’m saying a 17 caliber will weigh more then a 30 caliber if the contours and lengths are the same…more material is removed from the blank by drilling a 30 cal hole vs a 17 cal hole so the smaller caliber barrel will weigh more

 

[Clancy]

20 calibers are loud.

Smaller caliber barrels are heavier since less material is drilled out.

A good suppressor is a good suppressor, doesn’t matter much which round you run through it- within reason.

If you want a light rifle, look at building a Thompson Center.

Let me know if you find anything on a 6mm-fireball.

 

[L.Sherm]

I wouldnt lump all 20 calls as " loud" compared to what? A 20 on a 223 case or Br is gonna be comparable just like a 17 hornet to a 20 hornet or 17 time to a 20 tcm 17 badger to a 19 or 20 badger.

 

[linebaugh]

No idea what your intended use is and I dont care as long as you build a 6x221FB. Also you must report all results from this build... lol. Anything fireball gets me going so I may be slightly biased.

A good suppressor will kill a lot of muzzle blast and noise but you still have that supersonic crack. I believe there are a lot of cheaper/less reduction 223/ar suppressors out there so do your research and get a reputable one.

Sounds like the ppc/grendel case size may be in your wheelhouse.

 

[Coyotefurharvester]

In 50+ years hunting fox/coyote, the smaller the caliber/bullet weight, there is a lesser reaction to the actual sound of the firearm(suppressor or not). When stalking pairs of coyote or fox(sleeping during the day), shooting one and than having the second stop within range. The 17 rem was by far less disturbing (second animal stopped sooner) than 223,22-250 and larger. At night shooting suppressed the 20 cals seem to have the same effect. I haven't been using my 17 cals at night, because non are threaded for suppressors, A suppressed 22-250 is much better(less disturbance to animals) than any smaller centerfire unsuppressed.
I was going to run a thermal on a suppressed 18" AR 223 this winter, until I chronographed my best loads, the thermal is back on my suppressed 22" 204 Ruger bolt gun. If I want to go AR with the thermal I will put it on my 20p upper before any .22 or larger cal AR.
Mainly because I do put out baits/blinds and multiple opportunities (same night)for coyote are more likely when I run smaller calibers.

 

[JB10]

My 20 practical has less recoil and sound than a 223. I have not shot it away from a shooting range with out a suppressor on it. It is way quieter than an AR supressed. My 6mm-223 (6×45) with a 58gr vmax uses almost as much powder as a 223 with a 55gr pill.

 

[JSH]

If memory serves me, 6-221 and 7-221 were referred to/called Lasers. One of the IHMSA guys with a better memory may recall for sure.

 

[JSH]

4)ive heard that short fat cases are more efficient...how does this manifest itself ballistically...is it giving more propulsive efficiency, or more accuracy related

The PPC and BR case speak for them selves.

As far as I am concerned it is fact and not fiction.

 

[SteveOak]

hi i've not been on the forum for a while, i had a few questions that have accumilated, if anyone has answers, thanks

4)ive heard that short fat cases are more efficient...how does this manifest itself ballistically...is it giving more propulsive efficiency, or more accuracy related

First, let's define efficient in this case as greater muzzle velocity per given weight charge of powder for the same bullet. That the case will be necessarily of greater volume makes a direct comparison impossible so FPS/gr of powder @ maximum MV for the case will work.

PO Ackley was first to the game here. His cartridges were of a slightly larger diameter due to reducing the taper of the case from base to shoulder to a practical minimum. They also had a sharper shoulder, typically 40 degrees vs the common at the time 23 degrees.

I have no scientific proof but my hypothisis is the the sharper shoulder causes more of the powder to be burned before it is ejected from the case. This causes a more complete burn and yields higher pressure, resulting in the bullet being accelerated more and sooner.

Modern larger diameter cases drive a sharper sholder for the same shoulder length. The first that I know of was the 284 Win had a 30 degree shoulder to fit a larger diameter case to a 7mm bullet in a short action.