0.30" pellets in a 0.303" barrel?

[jackssmirkingrevenge]

As per title, curious if a 0.30" pellet like a JSB 50 grainer would be a good fit for a 0.303" firearm barrel.

[UCChris]

I'm so not an expert on the subject, but I would expect that the skirt would flare to .303" pretty easily. The head diameter is going to be the tricky part.

[rsterne]

AFAIK, a .303 firearm barrel measures 0.312" groove and 0.303" lands.... I have fired .30 cal pellets in a .30 cal firearm barrel that measured 0.300" lands and 0.308" grooves, and it wasn't great.... However, Tom at AAA did the same thing and said it was very accurate.... The nose of a .30 cal pellet is 0.300", so rides the lands, and the skirt, at 0.307-0.308" expands to seal OK in a .30 cal PB barrel.... I don't think it would be accurate in a .303 PB barrel, but it might "work".... It would NOT be a good fit, IMO....

I made a swaging tool to slightly shorten the .30 cal JSB pellets by tapping them on the nose to give a slight Meplat and expand them, and they worked great in a .308 barrel....

 

The pellets on the left of the die are the resulting "bumped up" diameter by shortening.... To the right are two pellets pushed through a .308 (groove) barrel, the one on the left is a bumped up, .308 diameter one.... and the one on the right a stock .30 cal JSB.... which hardly even touched the rifling.... The right hand picture shows the mandrel the skirt sits on before the front half of the die is tapped down to shorten the pellet....

Bob

[jackssmirkingrevenge]

Thanks for the input guys.

I had similarly swaged 0.22" pellets to fit the 0.24" barrel on the Apache Fireball though in a much more sloppy manner, it didn't occur to me that with the right tool it could be done consistently.

Looking ahead to putting together something with a bigger bore once I'm done playing with the Maximus.

[rsterne]

That tool consists of an upper "ram" (the long part) with a shoulder that limits how far into the lower "die" it can go.... Inside the ram are two holes, the larger one is drilled large enough (~1/2"? ) so that when you lower it over the positioned pellet you don't knock it off the rod.... The smaller recess (visible deep inside the ram in the right photo) is shallow, only about 1/8" deep, just slightly deeper than the length of the JSB pellet from the front to just behind the largest diameter of the head.... It holds the pellet straight during the swaging process.... In this case it was made with a 5/16" end mill, so is square bottomed and a few thou larger than the head after swaging, so it doesn't get stuck inside the ram....

The die consists of a bored hole that slides over the small end of the ram smoothly, and deep enough that it doesn't touch the end of the ram.... The inside rod is threaded into the die from the bottom, and has a screwdriver slot on the bottom end, so it is adjustable for height.... There is a cross-hole in the die containing a plastic tipped setscrew (I actually used a SHSS and a short plastic bar) bearing on the threads of the rod to lock the position yet allow adjustment.... The top of the rod is machined with a taper slightly wider than the inside taper on the skirt.... The blunt end is the same diameter as the flat inside the pellet skirt.... The taper is chosen to increase the skirt diameter by the desired amount when the end of the rod contacts the bottom of the hollow skirt.... If you want to increase the skirt OD by 0.008", then you need 0.008" more taper on the rod (in the length of the skirt) than what the inside of the skirt had originally.... I made the rod from a 3/8"-24NF  bolt....  so the taper is longer than required, but produces the exact skirt you want when pressed into the pellet so that the flat end stops at the bottom of the hole in the skirt....   

In use, the pellet is simply parked on top of the tapered rod, and the ram lowered over it and tapped until the shoulder on the ram hits the top of the die, giving a consistent length between the top of the rod and the inside of the die.... The inside of the die causes a flat (Meplat) on the nose of the pellet, and at the same time the taper on the rod slightly flares the skirt.... The top flat on the rod keeps the pellet from moving too far down the taper, and causes the head of the pellet to enlarge slightly as the Meplat is formed.... The distance between the top flat on the rod and the inside of the die is adjusted until you get the head diameter you want, the higher the rod is positioned, the more swaging of the head occurs, making the diameter of the head and Meplat both larger....

Anyway, you get the idea.... The shape of the taper on the top of the rod determines how much the skirt expands.... The distance between the top of the rod and the inside of the die determines how much the head expands when the Meplat is formed....

Bob

[jackssmirkingrevenge]

As always your attention to detail is appreciated, thanks!

[uncle paulie]

Bob, When sizing the pellets, what effect would the meplat have on the accuracy of a round nosed pellet, ie: JSB exacts?

pv

[rsterne]

Paul, I never had a chance to explore that in depth, but in the limited shooting I did (6 and 20 yards), it made an improvement over the undersized stock JSBs in the .308 barrel.... Comparing them to the same pellets in a different barrel would be pointless, right?....

What I can tell you is that the Meplat reduced the penetration, and increased the diameter of the wound cavity, when I tested it in soap.... and the pellet shortened somewhat compared to a stock one....

Bob

[SAGERAT NITEMARE]

The ONLY way to know FOR CERTAIN what size pellet works in what INDIVIDUAL gun it to test fire a few different brands, shapes and weights.

Every gun maker, country of origin, numerical destination(mm or inch) and individual barrel caliber has it's own characteristics...and what shoots bugholes in an FX, Daystate, Evanix or Gauntlet might spray the hillside in another gun of the same brand.  Each barrel maker produces barrels of varying ID's EVEN IN THE SAME CALIBER DESTINATIONS.

My three 25 cals shoot JSB 25 and 33 gr and 52 NSA with different accuracies and velocities and I can get the NSA's in different OD...and all actually slug slightly different ID's...

Try a few and see or slug your barrel and try to match a pellets' OD to YOUR guns barrel ID.

Good Luck

[uncle paulie]

My interest is in field target, shooting .177. I am finding a similar problem in that none of the pellets I have tried measure the stated die size advertised. Currently, the most consistent pellets I have found are the AA diabolo heavies. They are supposed to be 4.52, but they average 4.46( measured with two different calipers). At this point, I have no idea what size pellet my gun(HW100) would actually prefer. I do have a T.R.Robb sizing tool which will up-size pellets as well as reduce their diameter, but the up-sizing is quite inconsistent as it relies on hand pressure to operate. ie: how much is enough or too much.  I'm guessing I'll have to come up with a modification to control either the pressure or the travel of the push probe.

pv

[Gippeto]

Jack, it's a pretty simple job to whip up a little swage die in whatever size you need. These are for my 3240, and are a bore riding design with the driving band being at groove diameter + .001". Won't claim they're target grade, but they do smack cans quite well.

Al

[jackssmirkingrevenge]

Thanks Gippeto!

Won't claim they're target grade, but they do smack cans quite well.

That suits my "that looks about right" style...

What do they start out as though?  Round ball?

[Gippeto]

Those started life as OO buck. Have to size them down to fit into the swage die. Could use smaller round ball and punch more of a base into them to save a step.

Some of the .303Brit barrels are....looser...than others, and you'll need to slug the barrel. Have heard guys claim up to .314". If that were your case, these might also be an off the shelf option for you.

https://www.hornady.com/muzzleloading/browse/32-cal-315-lead-balls#!/

Could also just make a sizing die and shoot that result...


Al

[Bullfrog]

Like I’ve reported elsewhere, my .308 Texan SS loves .300 pellets both commercial and cast. So I’d say it would depend on the quirks of the barrel in question.

[rsterne]

As I said in my answer above, some report good results shooting .30 cal pellets in a .308 barrel.... However, .303's are nominally 0.312", and as Gipetto said, can be as large as 0.314".... I rather doubt the JSBs, with their .300" head and ~0.308" skirt would work in that.... but only by trying them would you know for sure....

Bob

[jackssmirkingrevenge]

I rather doubt the JSBs, with their .300" head and ~0.308" skirt would work in that.... but only by trying them would you know for sure...

I needed to order some JSBs anyway to feed a certain big bore pistol, I guess I'll give it a go.

Question about swaging on an amateur level, does one need a certain type of press or can one use something as basic as a bench vice to obtain reasonable results?

[Bullfrog]

Is the Daystate Wolverine 303 a true .303 barrel or is it something different like a .300?

[rsterne]

The Daystate is NOT the same size as a .303 PB barrel.... The ".303 British" has a long history in England, and they used that as a marketing tool.... Most likely, it is ~0.303" groove diameter (instead of land diameter)…. as that would work great with the JSB pellets (and vice versa)…. 

Bob

[Gippeto]

I rather doubt the JSBs, with their .300" head and ~0.308" skirt would work in that.... but only by trying them would you know for sure...

I needed to order some JSBs anyway to feed a certain big bore pistol, I guess I'll give it a go.

Question about swaging on an amateur level, does one need a certain type of press or can one use something as basic as a bench vice to obtain reasonable results?

Have a gros putain de marteau ?That's what I use. 

Al

[jackssmirkingrevenge]

Have a gros putain de marteau ?That's what I use. 

I do, right under my calisse de tabarnak de pinces

So a slow steady force or a couple of hard taps doesn't really affect the end result?