Slug-Only rifle: Makes sense? Barrel choice?

[Cableaddict]

My next pcp rifle may get a custom barrel.  Or not.  Either way, I'm trying to decide about barrel choice (twist rate, length, etc) and wether I should try to make a "slug only" gun.

Some caveats:

I don't imagine ever hunter at 100 yards or longer.   50 or less is typical.  My use of slugs is not for long-range accuracy, but primarily for mid-range wind resistance.  Also possibly for a straighter trajectory, but I'm not clear if that actually happens. Certainly BC is much higher.  It also seems there are more choices in heavy projectiles, if you go slug vs pellet, and my gun will be optimized to the max for fpe, so I'll be looking for the heaviest projectile it can accurately shoot.

2:  I will most likely keep the barrel at 20" or less, which I realize is not ideal, and which may require a different twist rate.  One exception is if I get the AEA HP Bullpup, which has a 24" barrel but a very short overall length.
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So my questions:

1:  Other than cost, is there any reason to ever shoot pellets, at all?

2:  Assuming I have enough fpe,   what would be the ideal twist rate for JUST slugs, in a 20" barrel?  In a 24" barrel?

3:  Do I need a choke?  Many folks say no, yet the FX slug liners are supposedly HEAVILY choked, so what the heck?

[Cableaddict]

Forgot to add:

I'm considering both 2.. and .25.   (I assume the twist numbers would be different.)


thx.

[Back_Roads]

 Unless you want to shoot very heavy slugs over 50 gr. you may find a gun that will shoot them with the factory barrel, but some minor power mods will most likely be needed.
 The Nova vista guns seem do do very well with slugs for eg. So may the AEA from recent reports, and are a good value from my experience so far.

 PS many new options are available since the pioneers of slug shooting blazed the trail for the next generation.

[CableStop]

The main draw back with slugs is air consumption, not only do they need to be going faster but they're usually heavier than a pellet which means it takes more air to get it up to a similar speed.  Most slugs like at least 800 FPS, but different styles and weights may favor different speeds so depending on slug and barrel combo it may shoot best at 1000+ FPS.  The flat base doesn't expand into the bore well compared to the flared base of a pellet so you also need enough energy to deform the slug and seal it into the bore or else you'll get blow by and waste as as well.  So with those points in mind slugs really only make sense in high power applications. 

Slugs generally need a faster twist rate than pellets since they don't have any flare to stabilize them but it depends on the type of slug you're shooting.  Boattails will need a faster twist rate than flat base slugs and generally shorter slugs need faster twists.  A lot of it comes down to the ballistic coefficient of the slug.  Barrel length doesn't effect the twist rate much since it doesn't matter how many twists are actually completed by the end of the barrel, the bullet gets its spin within the first few inches of the barrel.  Barrel length is important for increasing muzzle velocity and efficiency which goes back to the previous point about air consumption and speed. 

I honestly don't know much about choke, I was also under the impression that choke wasn't great for slugs but maybe FX knows something we don't.  The only thing I can think of is that looking into a smooth twist barrel, the rifling is actually very "smooth" compared to cut rifling, the edges aren't sharp, so maybe they need to choke the end to get a better grip on the slug.  Going back to the first point again, slugs don't expand as easily into the bore so the FX barrels may not bite in as well so they get the slug up to speed then tighten the bore down to force it to deform into the grooves better near the end of the barrel.

As far as slugs vs pellets for sub 50 yards I tend to prefer pellets, the accuracy and energy retention is similar enough that the savings on air are worth it to me.  However, in the current market slugs seem to be more available than pellets, I actually can't find any .25 Hades pellets in stock which are what my rifle is zero'd with.  If you plan on hunting expansion is important, and for larger game I'd recommend NSA slugs at any range since they give the best penetration and deformation in my testing compared to basically anything else on the market.  For raccoon and smaller at shorter ranges Hades pellets are great, but like I said I can't find any in stock.

[rsterne]

Keep in mind that at 950 fps, the FPE is twice the pellet/slug weight.... If you have a 50 FPE .25 cal, you aren't going to want to shoot much more than 25-30 gr., if it's up around 70 FPE, you will most likely want 35-40 gr., and if it's a 100 FPE gun, then you will only be shooting slugs, as there are no pellets heavy enough.... Pellets (which are flare stabilized) are very happy in a slow twist, about 100 calibers (eg. 22" in a .22 cal or 25" in a .25 cal) works great.... but those are likely too slow for most slugs, which are spin stabilized.... The longer the slug (heavy slugs are longer), the faster the twist you will need, therefore it is important to first assess the power level you want, and can achieve, before deciding on a barrel twist rate....

Bob

[ranchibi]

Tom, in .22 caliber, NSA and others do make lighter weight slugs that do not require too much air usage. I have a RAW (I know, too long) Chassis in .22 that I have de-tuned to shoot JSB 18gr @ 950fps and on that tune, shoots NSA 17gr @ 935ish. Groups well @ 20yds but tightens up a tad more @ longer distances (stabilize better). It's funny, even though the NSA are slower, @ 20yds (my zero), they hit 2 clicks higher (better BC I guess) and 4 clicks to the right than pellets. My suggestion would be for an Impact M3 or Maverick as you then have more than one barrel (twist and length) to choose from and can find out from others what barrel likes slugs and their size/weight. Have fun and good luck!

[Wayne52]

I personally cast everything that I shoot both pellets and slugs.  When I buy a gun I try getting one with an unchoked barrel.  I just checked NOE's situation on pellet molds in .22 and they have both 217-20-RF and 217-24-RF.   Both of those pellets shoot really good out of about any 22 cal airgun that I have.  The latest gun that I purchase is the AEA 357 Standard Challenger, now that gun has a 1-32" twist and shoots both pellets and slugs just great.  I'm very tempted to buy one of their small caliber guns because from what I've seen those are real powerful guns in comparison to most that are available (reasonably priced) on the market.  I even like the idea of one of their semi auto ones also because even those seem to have considerable power.  The one that I want isn't available right now but from what I've heard it's going to be a couple months before they have them back in stock.

[CableStop]

Tom, in .22 caliber, NSA and others do make lighter weight slugs that do not require too much air usage. I have a RAW (I know, too long) Chassis in .22 that I have de-tuned to shoot JSB 18gr @ 950fps and on that tune, shoots NSA 17gr @ 935ish. Groups well @ 20yds but tightens up a tad more @ longer distances (stabilize better). It's funny, even though the NSA are slower, @ 20yds (my zero), they hit 2 clicks higher (better BC I guess) and 4 clicks to the right than pellets. My suggestion would be for an Impact M3 or Maverick as you then have more than one barrel (twist and length) to choose from and can find out from others what barrel likes slugs and their size/weight. Have fun and good luck!

Thanks for pointing that out, I guess to clarify my statement I meant that pellets don't usually need 900+ FPS to shoot accurately where as slugs usually do.  If you only wanted to shoot the JSBs you could get away with a lower power tune and get more shots while preserving accuracy.  Also I don't know what I was thinking when I wrote shorter slugs need more twist, Bob is right that longer slugs need faster twist rates. 

[EdinGa]

My Hatsan Flashpup .25 shoots NSA 33.5s really well at 700 fps. I tried it after watching a Brothers in Air video, so I know mine isn't the only barrel that likes them. I can understand wanting a custom barrel, because I just ordered one myself, but there are choked barrels out there that don't care it you're feeding them slugs or pellets.

[Back_Roads]

 I may have been the one to nudge Brothers in Air into trying slugs, think he is glad he did, that or I'm one of them YOuTube airgun enablers

[Cableaddict]

My Hatsan Flashpup .25 shoots NSA 33.5s really well at 700 fps. I tried it after watching a Brothers in Air video, so I know mine isn't the only barrel that likes them. I can understand wanting a custom barrel, because I just ordered one myself, but there are choked barrels out there that don't care it you're feeding them slugs or pellets.

Sure, there are choked barrels that don't care it you're feeding them slugs or pellets, but they aren't OPTIMOZED for slugs, which is mainly what my query is about.

BTW -  With some minor drilling, the Flashpup can throw a 34 gr dish-based slug at about 860 fps.  (Ask me how I know  )     And from what I've read, the max some folks have reached, with added valve & probe work, is around 920 fps.
Of course, that's either unregulated, and just a few shots, or regulated with the reg maxed out, so again just a few shots.

- From what I've read, that same weight tends to be most accurate in the neighborhood of 950 fps. (Don't quote me on that)   Of course, different twist rates might help with accuracy at both above and below 900 fps,  which again is the main purpose of my query.

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Now let's take the case of something like the AEA HP Bullpup,  a very interesting rifle, to say the least. 
It's unregulated, and has been shown in chrono tests to sling 34 gr slugs at over 1030 fps. - That's not a misprint.
Sadly, the speed drops off like a cliff after about the sixth shot.  - but imagine cutting back its cylinder to around 100cc, then adding a drop block, regulator, and 500cc CF bottle.  The old cylinder is now a nice substantial plenum.  Set the reg output to 3,000 psi, and now you should have a decent string of shots at around 1,000 fps.   

But here's the issue:  Does that barrel properly throw 34 gr slugs at that speed?  Probably not.
Hence, dare I say it again,  this thread.   

[EdinGa]

I may have been the one to nudge Brothers in Air into trying slugs, think he is glad he did, that or I'm one of them YOuTube airgun enablers

So you're the one I can blame for being broke? 🤣