Min fps for reliable slug expansion in .357

I have an FX impact MK2 in .357


I’m currently hunting coyotes with it but have considered traveling to another state near me to hunt deer next season. 


I switched to griffen slugs as I found the 93 gr NSA were never expanding on coyotes on body shots. (Recovered a few) Grifffens are def softer. 


What’s the minimum fps for reliable expansion? 
I don’t have any ballistic gel, was going to try some water bottles to see. 
currently getting 837 fps with an 88 gr flat based HP. I am going to send it in to have the current power plenum installed to hopefully get that fps up some more for better expansion. 
83D2BF58-A894-40B2-B1DF-3FB25FAED394.1641940251.jpeg

 
at airguns speeds unless you got some really soft lead its 'not' reliable, not in firearm handguns either .. reliable takes about 2500fps and its a whole new ballgame of explosive meat damsge lol .. expansion at lower speeds really is a myth designed to sell you fancy pellets or handgun ammo .. at our speeds were relying on accuracy and penetration mostly and also base projectile diameter which is of course fixed with the gun .. so i suggest you just quit searching for the magic bullet and focus on the real factors ..
 
Sorry Mr. dizzums you missed the mark on this one.

There are plenty of 45ACP bullets with very good expansion in the 850-950fps range.

https://www.outdoorhub.com/reviews/2018/08/06/3-reasons-to-choose-the-45-acp-by-the-numbers/

Plenty of good soft lead slugs that expand well at the same velocity. Some pellets even expand well at lower speeds.

Here is a vid on some .22 slug expansion in the mid 1000fps range.

https://www.bakerairguns.com/general/22-caliber-airgun-slug-shootout-jsb-k-o-slugs-first-look/


 
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MrHollowpoint.com makes quite a few offerings in 357. The Benjamin Bulldog shooters seem to really like his slugs and it shoots around the same energy as your FX in stock form. I would probably get in touch with him and see what he says. I don’t think he will give you bad information just to sell you a few slugs. I would also not rule out a traditional pellet if the accuracy is much better than any slug you can find. I would definitely give the Polymags a try if you can’t find a slug that will group well. 
 
🔹dizzums,

tests seem to show that impact velocities above 800fps strongly favor HP expansion.





🔹bigbuck

sorry that I only have collected .22cal data.

However, I would assume that expansion increases with larger calibers exponentially — as more tissue has to either get out of the way of the projectile — or gets slammed into the HP cup, making it expand more....



Matthias 😊



PS: I have several dozen of these expansion tests graphically summarized like the one posted here.





Projectile Tests. PT026.  Steve Scialli AEAC 2020. -Ballistic Gel Calibrated.- 41-46FPE. Bc Hu...jpg

 
I have just completed a ton of testing using Clear Ballistics Gel with my Benjamin Bulldog .357. With NSA 110gr, I could not get expansion at 850fps, and the expansion was minimal at 950 with the 79gr slugs. I believe this is due to the thicker sidewalls on the ammo. When shooting the 142gr NSA slugs at 750fps, I got much better expansion, as those slugs have a much thinner sidewall than the 79 and 110gr slugs do.

20211216_200221.1642045521.jpg
20211216_184200.1642045522.jpg


The 79gr was almost a full pass through at 10 yards, while the 110gr and 142gr zipped right through the entire 16 inch gel block. I'll have a video ready to post on Friday.
 
I also disagree with needing extreme speed for slug expansion. Here’s a few pics of a couple .25 fx hybrids recovered from squirrel noggins. Leaving the muzzle at 990 fps from my cricket ll
9F08D6D3-18D2-4AB8-B06D-901FE135C6B1.1642278672.jpeg
D79A0E36-5864-4DCA-ABE6-E6C26FD9567D.1642278673.jpeg
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B938A735-3288-4DDD-995B-02D7B571C071.1642278676.jpeg

IIt all depends on the design of the slug and the hardness of the lead alloy. My test findings only apply to NSA .357 cal slugs. I just got some .30 cal FX Hybrid Slugs in and I'll test them next week with my Argus.
 
I shot the griffin slugs today in my 30 cal, they have some awesome ammo. The LDC slug uses a smal ball to aid expansion. The 50gr flat base LDC slug shot the best out of AGT Uragon. Hot 836 fps (Upper right) I just ordered a new M3 so I’m excited to see if it likes any of his LDC in .35



estarky soild work. I was going to use water and see what I get for expansion. 
5FB9A9ED-5863-49D3-96CB-2FFC4CE21A37.1642377272.jpeg

 
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Love the Benjamin bulldog for turkey hunting and the grizzly went through so I tried the polymag and it was good but not much expansion if any. I bought some NSA 79 when they were set up in MO and have not tried them yet. Still looking for a good slug for turkey hunting


@John1205 Wait a minute. You were able to hit something you aimed at and killed it shooting .35 H&N Grizzly slugs from a .357 Benjamin Bulldog? Tell me more. Do you have any pictures? Is this a stock Bulldog?
 
Love the Benjamin bulldog for turkey hunting and the grizzly went through so I tried the polymag and it was good but not much expansion if any. I bought some NSA 79 when they were set up in MO and have not tried them yet. Still looking for a good slug for turkey hunting


@John1205 Wait a minute. You were able to hit something you aimed at and killed it shooting .35 H&N Grizzly slugs from a .357 Benjamin Bulldog? Tell me more. Do you have any pictures? Is this a stock Bulldog?

Ditto!

H&N Grizzly turned my Bulldog into a shotgun! Horrid groupings at 50 yards.
 
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I have an FX impact MK2 in .357


I’m currently hunting coyotes with it but have considered traveling to another state near me to hunt deer next season.


I switched to griffen slugs as I found the 93 gr NSA were never expanding on coyotes on body shots. (Recovered a few) Grifffens are def softer.


What’s the minimum fps for reliable expansion?
I don’t have any ballistic gel, was going to try some water bottles to see.
currently getting 837 fps with an 88 gr flat based HP. I am going to send it in to have the current power plenum installed to hopefully get that fps up some more for better expansion. View attachment 190985
To the OP. I have actually just gone the other way towards 93grain nsa slugs in my impact m3. I had to get the tungsten hammer put in to push those at the speeds they like. For me that’s right around 920. I do have some upward mobility but they group well. Previously I had too much expansion using exclusively the FX Hybrids. Those are a fantastic round but they lacked the penetration needed to really down a coyote. I have learned talking through the same things with the kind folks here that with larger game penetration is 1st, second, and third in importance. So while coyotes don’t come around often this time of year I’ve been doing well on larger raccoons. The NSAs will pop open their heads, leave grey matter everywhere and hit the tree behind with enough force I worry about waking the neighbors :). I do think it will do the trick on my coyote problem this winter. If you find a better slug let me know. I’m always eager to learn. I will say if you want your 93grainers to really move your gunna need the reg set around 160-165 with hammer spring essentially maxed out, and the tungsten hammer. I’m at 6 lines on the front dwell valve. So my most important note though was without that 20-30$ tungsten hammer I couldn’t get more than around 800fps with my M3 with 800mm slug barrel. It’s important. Best of luck, keep in touch if you find a great coyote killer that works well in our guns :).

 
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at airguns speeds unless you got some really soft lead its 'not' reliable, not in firearm handguns either .. reliable takes about 2500fps and its a whole new ballgame of explosive meat damsge lol .. expansion at lower speeds really is a myth designed to sell you fancy pellets or handgun ammo .. at our speeds were relying on accuracy and penetration mostly and also base projectile diameter which is of course fixed with the gun .. so i suggest you just quit searching for the magic bullet and focus on the real factors ..
Facts
 
🔹dizzums,

tests seem to show that impact velocities above 800fps strongly favor HP expansion.





🔹bigbuck,

sorry that I only have collected .22cal data.

However, I would assume that expansion increases with larger calibers exponentially — as more tissue has to either get out of the way of the projectile — or gets slammed into the HP cup, making it expand more....



Matthias 😊



PS: I have several dozen of these expansion tests graphically summarized like the one posted here.





At View attachment 191065
At what range are you placing the gelatin block for expansion tests? Are these pellets/slugs at 800++ FPS at reasonably normal hunting distances?