What type of slug in tj barrel?

Was wondering what type of slug works in your tj barrel? So mine is currently used in a flex .30 cal and has no choke. I’ve had the gun sitting for a couple years and now that I live on 42 acres I’m shooting a lot again. The barrel shoots jsb 50 grain pellets very nicely but that isn’t a surprise. Just curious what any of you with a tj barrel use for slugs? I’m not 100% on the twist rate but I think it’s 1:14? Anyways look forward to your feedback.
 
40-70...my bad😅

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Well I do know it doesn’t have a slug liner so it must be one of the others. I just know I got one without a choke so I could try slugs out of the Flex. It’s currently on the flex and shoots pellets beautifully, was considering just getting the sample .30 cal pellets from NSA. I’m hoping to use a lighter slug just so I can push it fast and keep shot count up. Right now it will push the 50 grain jsb over 1000fps no problem. But they only work well at 880-900 fps. I appreciate the feed back and was just hoping someone had some real world experience with tj barrel and slugs.
 
Motörhead you had the flex, is that what barrel it came with? 1:26?
Never started as a Flex, but an R&D .177 for FT duty in WARP configuration. Threw the years many a barrel was fitted, valves and internals changed with tune adjusted.
Said ... quite a few TJ barrels in WAR fitment passed over the bench. 1:26 for the .30 was there OEM specified twist as i witnessed.
As was JSAR years later.
 
Ok so finally got some results as I ordered 3 different slugs. 1. FX hybrid slugs .30 @ 44.5g. 2. NSA .30 @ 43.8. 3. NSA .30 @ 49.5.
My flex currently shoots the JSB 50 grain pellets at 905fps making right around 90fpe. I did not change anything when testing these slugs out.
1. FX slugs at 55 yards were 2-3” groups and they sounded to be tumbling or something cause you could hear them zinging. (Maybe because these are a hybrid they might need to go slower?) not to sure but definitely not liking the speed they are at.
2. NSA 43.8 had to be the best results and were grouping around .75”. I figure these are moving around 950-970fps but I didn’t crony them to verify
3. NSA 49.5 did ok at 55 yards, 1.5” groups but you could tell they wanted to group better and I think it is just fps related. Most likely they would do better if they were going faster.

Overall I like the idea of shooting a lighter slug to increase shot count and have faster flatter shooting slugs. Also with a bit of tuning I’m sure I could improve the performance of the slugs for NSA 43.8 grains.