Precihole's new custom pellets - a test report

[Basu]

Dear benne,
It is not very clear from the pic about the thickness.
However ,my understanding is that a thinner skirt gives higher velocity.
Hope this pellet will produce optimum FPE in Orion.

Basu

[bennedose]

Dear benne,
It is not very clear from the pic about the thickness.
However ,my understanding is that a thinner skirt gives higher velocity.
Hope this pellet will produce optimum FPE in Orion.

Basu

At the very edge, MSRH is marginally thicker on Vernier caliper measurement. Deeper inside MSRH is much thicker and the Precihole pellet looks like that inner mass has been cored out neatly leaving a larger cavity.

[Big Daddy]

Brihaji, it's really nice to know the country is now getting "self reliant". First with the introduction of an indigenously made gas ram and now good pellets. With G Simth and Precihole, we have two good pellets. Would love to see a comparison between the two. Would sure be interesting.

BD

[brihacharan]

Is the thickness of the skirt less than MSRH ?

Basu

Yes. See image. MSRH is on the right.

preci_msrhexpo.jpg

> How very interesting ....
> First Bennedose's exhaustive report...Second Basu's query on the comparison with Mastershot....
> Nothing can be more evident & revealing than the "Photographs" presented by Bennedose....
> The finish & configuration of the Precihole Pellet on the left is perfectly engineered while that of Mastershot on the right is crude & of poor finish.
> The inference is clear & positive....if you know what I mean!!!
Briha

[bennedose]

> How very interesting ....
> First Bennedose's exhaustive report...Second Basu's query on the comparison with Mastershot....
> Nothing can be more evident & revealing than the "Photographs" presented by Bennedose....
> The finish & configuration of the Precihole Pellet on the left is perfectly engineered while that of Mastershot on the right is crude & of poor finish.
> The inference is clear & positive....if you know what I mean!!!
Briha

There is no comparison.

One final tidbit. Precihole's pellets will also please the velocity freaks. It's energy at 25 meters is spectacular (Using Orion to shoot)

[brihacharan]

Dear benne,
It is not very clear from the pic about the thickness.
Basu

Basu
I hope you don't need an "Electron Microscope" to decipher the clarity between the two images
Cant you see the difference in the "ID" of the two pellets????
The visual is both implicit & amply revealing....QED!
Briha

[Basu]

Dear Briha,
The difference in ID does not necessarily indicate the thickness of the skirt spcecially when both pellets having different OD.
Measurement by a caliper is the best answer.

Basu

[brihacharan]

Dear Briha,
The difference in ID does not necessarily indicate the thickness of the skirt specially when both pellets having different OD.
Measurement by a caliper is the best answer.
Basu

Hi Basu,
> Air guns generally use a slightly undersized projectile that is designed to expand upon shooting so as to seal the bore by engaging the rifling to fit the bore in order to form a tight seal.

> The DIABLO is the most common design which tapers to a thin waist. From the waist, the pellet is hollow, and flares out to full diameter of the air gun’s breech.

> This keeps the pellet centered in the bore, while keeping the friction as low as possible. The effect of friction is used in order to keep the pellet stationary until the piston has reached the end of its travel, compressing as much air as is inherently possible.

> The skirt of the pellet is made thin, to fit the bore and provide a good seal thereby imparting a spin to prevent the pellet from tumbling during its flight.

> The skirt of the DIABLO pellet grabs the rifling, sealing the air, which yields the best and highest efficiency while the wasp waist ensures less air resistance & make it more aerodynamic.

> Of course a thinner skirt is ideal, since it can “Obdurate” (expand in shape) when subjected to high pressured air released from the transfer port.

> However a pellet which has a thinner skirt, but its hollow space is not sufficiently large enough (due to bad / poor manufacturing) cannot have the advantage of receiving the optimum air pressure when the AR if fired, which is the determining factor for velocity & accuracy.

> Now see the pics of Precihole Pellet & that of Mastershot closely & you’ll find that the former’s hollow space is larger & better defined (while that of the latter appears congested) thus enhancing the capacity & capability to take the maximum energy released by the AR’s piston.

> IMHO - while the dimension of the pellet skirt is important, it’s not the sole determining factor contributing towards optimum velocity and accuracy.
In conclusion one can surmise that, the “innocent” looking pellet has much more to it by way of its’….
1. Metallurgical composition
2. Overall design…
a) Head size & shape
b) Consistency in the taper of its waist
c) Uniformity in its flare
d) Uniformity of skirt thickness
e) Optimum hollow space
f) Good manufacturing practice

Briha

[bennedose]

> The skirt of the pellet is made thin, to fit the bore and provide a good seal thereby imparting a spin to prevent the pellet from tumbling during its flight.

> The skirt of the DIABLO pellet grabs the rifling, sealing the air, which yields the best and highest efficiency while the wasp waist ensures less air resistance & make it more aerodynamic.

> Of course a thinner skirt is ideal, since it can “Obdurate” (expand in shape) when subjected to high pressured air released from the transfer port.

> However a pellet which has a thinner skirt, but its hollow space is not sufficiently large enough (due to bad / poor manufacturing) cannot have the advantage of receiving the optimum air pressure when the AR if fired, which is the determining factor for velocity & accuracy.

Good post Briha. The other thing is that the air pressure expands the skirt by a few micrometers to enhance the seal. If the skirt is of irregular thickness or the pellet distorted (oval) the seal itself becomes irregular. So a skirt of uniform thickness and perfectly circular shape is desirable. That is unfortunately absent in those Mastershot pellets.

[mercury]

great work Bennedose...those PH pellets look very good.

two quick points though.....nit-picking..hair splitting...what ever , but with no malice ;

CALIBER:
The Vernier shows a diameter of 5.75 mm. This is remarkably constant from pellet to pellet. Compared to this, GSmith round head pellets gave me a caliber measurement of 5.6 mm. .

measuring the head size on a pellet is a little tricky. the skirt of a pellet is slightly larger than the head and measured the way you have done.....you will have the skirt size. one method you can try is to place the pellet on the caliper and gently open the jaws till just the head sags down and the tail stays out. make sense ?? its late will try and put up a picture tomorrow......IF I can get my hands on a caliper !

WEIGHT:
Each pellet is exactly 1 gram (15.43 grain). This compares with 1.1 grams (16.97) of Gsmith round head (high impact). difference.

you sure that's the weight of a Gsmith (high impact) pellet ? my understanding is that they are in the 19grn range.

[brihacharan]

great work Bennedose...those PH pellets look very good.

two quick points though.....nit-picking..hair splitting...what ever , but with no malice ;

CALIBER:
The Vernier shows a diameter of 5.75 mm. This is remarkably constant from pellet to pellet. Compared to this, GSmith round head pellets gave me a caliber measurement of 5.6 mm. .

measuring the head size on a pellet is a little tricky. the skirt of a pellet is slightly larger than the head and measured the way you have done.....you will have the skirt size. one method you can try is to place the pellet on the caliper and gently open the jaws till just the head sags down and the tail stays out. make sense ?? its late will try and put up a picture tomorrow......IF I can get my hands on a caliper !

WEIGHT:
Each pellet is exactly 1 gram (15.43 grain). This compares with 1.1 grams (16.97) of Gsmith round head (high impact). difference.

you sure that's the weight of a Gsmith (high impact) pellet ?
My understanding is that they are in the 19grn range.

> I agree
> My assessment of GSmith's RH High Impact done on a highly sensitive electronic balance (Mettler) gave reading of an average of 19.1gr...
> However the noteworthy feature of GSmith pellets is their wt. is consistent...
Briha

[bennedose]

two quick points though.....nit-picking..hair splitting...what ever , but with no malice ;

CALIBER:
The Vernier shows a diameter of 5.75 mm. This is remarkably constant from pellet to pellet. Compared to this, GSmith round head pellets gave me a caliber measurement of 5.6 mm. .

measuring the head size on a pellet is a little tricky. the skirt of a pellet is slightly larger than the head and measured the way you have done.....you will have the skirt size. one method you can try is to place the pellet on the caliper and gently open the jaws till just the head sags down and the tail stays out. make sense ?? its late will try and put up a picture tomorrow......IF I can get my hands on a caliper !

WEIGHT:
Each pellet is exactly 1 gram (15.43 grain). This compares with 1.1 grams (16.97) of Gsmith round head (high impact). difference.

you sure that's the weight of a Gsmith (high impact) pellet ? my understanding is that they are in the 19grn range.

I was a little surprised at the 5.75mm result. I got the same result with 2 or 3 pellets and did not take it further and posted the info as I got it. I found Precihole's pellets an exact fit into the Orion - requiring a very gentle push. GSmith are a slightly loose fit and can fall out if I tilt the breech down and give the cocked rifle a mild jerk. So the difference in size is real - although the absolute measurements are surprising.

The other doubt I have regarding "bore" is whether the measurement of the bore is from depths of rifling groove or from peak of rifling ridges. That could make a difference between a measurement of 5.6 and 5.75

I rechecked the weight today and yes they (GSmith round head "High Impact") are 1.1 grams and not 1.23 grams (19 grain).
GSmith Flat heads are lighter - at 1 gram each
GSmith steel tipped are the same as round head - 1.1 grams each

This time I weighed the pellets using an electronic scale and Precihole weighed in at 1 gram exactly, so it is unlikely that only the Gsmith weights are in error. On a previous occasion I had used an ordinary kitchen scale to weigh Gsmith pellets. I had first marked the position of the scale pointer with a standard 50 gram weight. I then added pellets to the tray until I reached the 50 gram mark Didviding 50 by the number of Gsmith pellets also gave me around 1.1 grams, if I remember correctly. I posted it somewhere on this forum - I will check and locate that post.

[brihacharan]

Hi Guys,
> Pellets - A very interesting subject for research & debate
> As an extension to the spiel that's going on....here's some from me

Pellet Quality:
Quality is the most important variable in pellets and it varies enormously from manufacturer to manufacturer. Greater the variation means poorer the accuracy, larger groups and more misses!

While the cost difference between popular poor quality pellets & the finest pellets at least in India may be a shade too big, remember that low-quality pellets can actually injure your air-guns. Irregular shaped & inconsistent weight pellets allow excessive air blow-by. Thus for spring piston guns, this means less air cushioning for the piston.

The resulting jarring reduces the life of the piston, seal, mainspring and other parts besides loosening sights and screws that hold the action to the stock. It also causes shooter fatigue. Poor pellets simply are not worth the false economy.

Composition of Pellets:
Almost all air-gun pellets are made of soft lead. No other material seems to offer such an excellent combination of weight and density, workabilty, rifling engagement, air seal, inertia, expansion upon impact, and resistance to ricochet.

However small amounts of antimony and tin are sometimes added / alloyed into pellet lead to increase its hardness. Harder pellets resist handling and loading damage better, but they also may resist proper engagement by the rifling, and reduce velocity through increased friction and air blow-by.

Penetration is increased, but expansion is reduced. A hard pellet may appear more effective in tests because of its greater penetration, but in use on game it probably would be less effective than an expanding pellet.

A typical analysis on pellet lead is of the British Standard No. 602: 1956 II:

•Lead - not less than 99.25% and not more than 99.80%
•Antimony - not more than 0.10%
•Zinc - not more than 0.005%
•Copper - not more than 0.07%
•Tin - not more than 0.50%

Top quality international brand pellets are 99.9% Lead and 0.05% Antimony. The addition of antimony has three purposes:

1. To improve the swaging process.
2. To protect the pellets against transportation damages.
3. To improve resistance to corrosion due to oxidation.
4. To maintain consistency in weight & dimensions.

Briha

[mercury]

Bennedose.......could not get a caliper , but spent the day trying for a picture online and bingo....



there may be other ways..... but I had a friend who did it this way.

I have a tin of ely wasp 5,6mm for my mercury. I have a tough time getting those pellets into the breach of my 350. that's the reason the 5.75 and 5.6 head sizes for the PH and GS don't sound right.

Briha ...you are right , I have found the newer batch of g smith pellets to be very consistent in fit too. I am looking forward to the PH pellets , because going by Bennedose's measurements , they are larger than GS which are a slight loose fit on my 350.

[bennedose]

Bennedose.......could not get a caliper , but spent the day trying for a picture online and bingo....

Brilliant. I have learned something today. I had posted skirt sizes.

Precihole pellets heads are exactly 5.5 mm using this method.
Gsmith round head are exactly 5.4 mm at the head

However the weight of GSmith round head pellets is defintely 1.1 grams or 16.97 grain

I have confirmed this by testing my scale with a known 10 gram gold weight and adding 10 Gsmith pellets to total 21 grams - making each pellet = 1.1 grams
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