Precision ballistics 10.5 grn slugs

[Ultrastu]

So thanks to an awesome pigeon watch member on this forum I've been lucky enough to be testing these brand new slugs over the weekend .

First caveat .its been pretty windy sat and Monday. 

So these slugs weigh 10.5 grns and are 4.49 mm in diameter and about the same length as a jsb exact .

First I  tested them out of a sub 12 bsa scorpion at 25 yds (this gun is super un pellet fussy ) it will just shoot any half decent pellet really well .this was in my sheltered garden I put them over the chrono and they dropped around 1/2 an fpe at the muzzle compared to its usual air arms fields .I shot 2 test groups with the pellets first. (Zero was a touch off on group 1 so rezeroed for no 2 ,  and then didn't touch the turrets after that )as you can see the pellets shot pretty well groups 3 ,4,5 were the slugs .as you see the groups started  to tighten up in group 4 and then 5 but then threw the last 2 shots very high and right .so I gave up on them.

As really I feel fac is were these may shine .

Tbc.

[Ultrastu]

So Saturday was a field test with the 10.5 grn slugs with the fac scorp running around 18 fpe with jsb 8.4 grns .

The slugs still dropped around 1/2 fpe to 17.5 ish .groups out in the open and wind were far from conclusive but one thing that was noticeable was that the slugs dropped more on target than I was suspecting them to at 50 yds they also showed similar wind drift to the pellets. But the wind was all over the place so abandoned the test as a bad job .

 

[Ultrastu]

So to today .Still very windy .but this time I set up in a barn and shot out of it so had 25 yds sheltered before 25 or so yards in the wind (with some protection from farm machinery .) I initially  set up at 45 yds which is the zero point for the exacts at 980 fps .I had chronos .both 10.5 grn slugs and 13 grn ones and lots of different pellets  ,I fancied seeing if any my other pellets could handle speeds around 1000 fps  as good as the jsb .(turns out they all do - falcon Acc  plus at 1020 fps  put in some cool groups at 45 yds ) 

Back to the slugs .the take away is 

These 10.5 grn slugs drop much more than pellets and the same amount as the heavier 13 grn ones the wind drift is about the same as the both the others too but this wasn't really a wind test as I was trying to shelter from it as much as possible and what was there was multi directional .

My gun shot a few decent groups with them one at 65 yds that was as good if not a touch better than the pellets .

Slug speeds were around 865 fps 

By using projectile drop at range to estimate the bc of these slugs to my known pellet bc and 13 grn bc .I estimate the 10.5s have a bc of around 0.032 .

Which for a slug is very low .and similar to the jsb heavies  at 10.3 grns (bc 0.031)

This gives these slugs no trajectory  or energy advantage over a 10.3 grn jsb and much less trajectory than 8.4s and only a small increase in energy retention  over them .this is lost due to the initial muzzle energy drop .With  these comparable bc s between pellets (8.4 grn = 0.025 ) and the slug I'd expect to see no wind drift advantage either .and my tests this weekend have indicated this to be the case .

So with the above in mind these slugs seem to forgo the high bc normally accociated with slugs and the accompanying  benefits of trajectory ,wind drift ,energy retention  and I suspect expansion) 

My gun shoots these slugs reasonably accurately so it's fair to suggest the bc's are relevant and likely to be found in other guns also .

The cost of these slugs is very high and I'm struggling  to justify  them over the awesome jsb exact .where the jsb just go where you expect them to the slugs can be a bit hit and miss (literally ) 

So far I'm more impressed with the 13 grn slugs with a bc of 0.07  .

[Ultrastu]

Pellets top ,aim point to the left 

Slugs lower down, aim point to the left and up .

This was 65 yds and the best group the slugs shot .and the worst group the pellets had shot .but it demonstrates the drop difference .

[Ultrastu]

So the graph is a drop chart for sub 12 airguns for the 10.5 grn slugs at 10.5 fpe Green 

Pink is jsb heavy at 11.5 fpe 

Blue is jsb 8.4 at 11.3 fpe 

Red is fac slug at 17.5 fpe .

The apogee  s have been optimized for fairness  as you see  these slugs don't give give any trajectory  advantage .and wind charts show the similar trend  

[Ultrastu]

[Mice!]

Good test there Stu, shame they haven't lived upto expectations. They looked to have grouped ok but not as well as I'd want.

Did they load ok? Few lads on the Agf have had issues with them in magazines. 

 

[villaman]

Nice bit of testing 

[figgy]

When I looked at the strelock pro data for them, I was disappointed to see the drop wasn't much better at 100m than for jsb heavies same for wind.

Not what I been led to believe of slugs. Just shows the shape without the extra weight isn't much of an advantage.

[Ultrastu]

4 hours ago, Mice! said:

Good test there Stu, shame they haven't lived upto expectations. They looked to have grouped ok but not as well as I'd want.

Did they load ok? Few lads on the Agf have had issues with them in magazines. 

 

They didn't load to well in my mk1 bsa blue mag .they tip in the mag somewhat .

I have a mk2 blue mag in my sub 12 and they seemed OK in that .my mate tried some in his fac also with mk2 mag and again they loaded ok .

My mate wasn't super impressed either on Saturday. (Again not a fair test in the wind) 

Cheers mice .

[Ultrastu]

1 hour ago, figgy said:

When I looked at the strelock pro data for them, I was disappointed to see the drop wasn't much better at 100m than for jsb heavies same for wind.

Not what I been led to believe of slugs. Just shows the shape without the extra weight isn't much of an advantage.

It's funny how the 13 grn slug seems to punch above its weight bc wize .

And the 10.5 grn below what I would have expected .(I expected around 0.045 - 0.055 ) to be honest I'm not really seeing a big advantage for these slugs over pellets in .177 .certainly not at sub 12 and even at the energy I'm shooting them at 18 fpe .they still don't seem to be a game changer (cost I always a factor ) .I think to get the best out of a .177 slug  it would have to be a 13 / 15 grn going around 950 - 1000 fps .

This would require a long barrel and a big bottle to get the shot count at those speeds .then I could see them being great for night time rabbiting or maybe birds on a windy branch .

But for what I have , I think the humble pellet is still a hard act to beat .

[Ultrastu]

I've still got around 100 left .so I will get them over the dual chronos and confirm the bc .and also do my bacon expansion tests at sub 12 and 17.5 fpe .

I did shoot a plastic bottle full of water and they made  it jump quiet violently .

For what's thats worth

[Mice!]

49 minutes ago, Ultrastu said:

I've still got around 100 left .so I will get them over the dual chronos and confirm the bc .and also do my bacon expansion tests at sub 12 and 17.5 fpe .

I did shoot a plastic bottle full of water and they made  it jump quiet violently .

For what's thats worth

I wondered if you would still do the expansion test or not.

Do you think them being a fraction bigger on the diameter would make any difference or is it going to be a weight issue?

[Ultrastu]

I dont think the diameter is the issue .

There is just so little baring surface to contact the rifling .

There is also very little mass behind the front hollow point this may ? Lead to a lack of expansion  on impact with flesh as there is so little to drive the mushrooming effect .

You see this with the prohunter 13 grn  high impact slugs .(they expand less than the standard version ) which I shoot .

Again to be confirmed, I might be wrong .the higher speeds may make up for the lack of rear weight. 

[bruno22rf]

So all we have really learnt is that Stu 's other half most likely spent most of her easter hols looking for her Bacon.

[figgy]

I think expansion is where they will win over pellets.

[wymberley]

Think I'll stay with the JSB Exact Heavy. 5 shot group at a measured 40 yards through a BSA R-10TH 177:

https://ibb.co/Tv7sBg4

[Mice!]

1 hour ago, wymberley said:

Think I'll stay with the JSB Exact Heavy. 5 shot group at a measured 40 yards through a BSA R-10TH 177:

https://ibb.co/Tv7sBg4

Very nice, have you started testing now then?

[Ttfjlc]

9 hours ago, figgy said:

I think expansion is where they will win over pellets.

Only if you manage to get them on target in the first place 

[figgy]

Can't argue with that.

[Ultrastu]

Well hopefully the weather will be a lot calmer this weekend..

I will try them again for accuracy  at range ,bc confirmation and expansion tests also  .

Have you tried any yet figgy ? 

[figgy]

No still waiting on delivery, they were posted last Wednesday. If they don't turn up by Saturday I'm getting a refund as it looks like they gone missing in the royal mail black hole. Everyone else seems to have gotten theirs last week.

I've been leading my barrel in readiness of trying them. 

Even looked at wildman as they're just down the road but they've sold out of 11.8 grain slugs. I may at some point try some 13 grain just out of curiosity.

Edited April 8, 2021 by figgy

[Ultrastu]

So an update to these slugs and other projectiles while I'm at it .

So today I got out my single shot competition  bsa ultra (its my comp gun because its easily my most accurate bsa ever ) .I chose this as being single loading I can negate any potential  magazine feed issues with the slugs .the idea was a bit of garden accuracy  testing but mainly bc calculations  with 2 chronos  at 20 yds (my standard range for this ) 

First up 5 jsb exact 8.4s the guns fave pellet .followed by 5 10.5 grn slugs 

As you can see the pellets made a single hole at 25 yds  the last shot dropping a couple of mm low to ruin an almost perfect 4.5 mm group .(probably my fault .) The slugs  not so great  and dropped too  .

After that I got the chronos out and set about bc testing the pellets and slugs .

 

 

[Ultrastu]

So I fire 5 shots and take the average start speed and average end speed and use chair gun to calculate the average bc .this works well for me .

Pellets 

Jsb 8.4 grn   bc 0.026 

Jsb monster 13.4 grn  0.027 

Jsb beast  16.2  grn   0.036

Slugs 

Precision 10.5  grn bc 0.0265 

Pro hunter 13 grn bc 0.051 

So as you can see today out of this gun the exacts gave a very high bc for a .177 med weight pellet the monsters and beasts  following a predicable trend of more mass =higher bc .(the beasts were very accurate  also ) 

The slugs the 10.5 grn ones gave almost the same bc as the 8.4s which was lower than I'd previously  guesstimated at 0.03 

And the 13 grn slugs a bit lower too at 0.051  I predicted around 0.07 (but to be fair these were when shot from a fac airgun so there may be a difference there ) 

Also worthy of note was the shot velocity spreads  the exacts gave only 6 fps difference over the 5 shots at the muzzle and only 7 fps difference at 20 yds .this obviously leading to the incredible  accuracy  the 13 grn slugs had a  very similar speard of 7 and 8 fps  the 10.5 grn slugs gave 19 fps at the muzzle and 21 fps at range  this I guess also goes to explain the random points of  impact on paper  

So the take away from all this .

Pellets awesome 

Slugs er not so much .

I'm disappointed to read a bc of 0.0265 for these 10.5 grn slugs .that's similar to a 10.5 grn Bisley magnum and lower than a 10.3 grn jsb heavy .

They Rob energy from the gun and don't perform in bc or accuracy  (wind drift is generally a function of bc ) so won't be exceptional  in the wind either  .

I guess their only redeeming factor could be expansion on impact (yet to be tested .) 

Cheers  stu 

 

 

[Mice!]

Nice work Stu, no wonder everything likes JSB exacts. 

Bring on the bacon 😅😅 fella did some interesting things with gelatine the other day, good because you can see the path the pellets have taken.