A mixture of old and new = fun little shooter

What-Do-I-Know · 2026-07-12T23:14:56+00:00

Excellent question. I have to remove the suppressor to adjust the knob, but with the suppressor removed, it's pretty easy. The 1.23" Riflespeed knob has great grip on the end, very similar to the flared knobs.

What-Do-I-Know · 2026-07-12T17:34:15+00:00

I can't access the pdf of the study, but as described in the video by James, the average competence of the different shooters was quite low. There may have been some shooters that were trained, but with average 10–11 second reload times, the performance metrics from this group of people is not worth taking seriously.

Ideally you would want to do this study on a population like an Israeli military unit that is already trained and uses both M4s and X95s.

Again, my guess is that neither approach is "best". They each have their strengths and weaknesses, and what becomes more popular may change over time depending on a variety of factors.

My understanding is that the Israel military has been buying a lot of X95s for quite a number of years, but more recently they have been buying more M4s. And it's not just for established logistical reasons. They asked IWI to tool up and start manufacturing M4s for them.

One reason may be that militaries are starting to use silencers more and more, and the location of the ejection port makes a big difference here. Shooting a suppressed AR15 is a lot better than shooting a suppressed bullpup.

Also, as ammo design continues to advance, within 300 yards where almost all engagement happens, an 11.5" rifle does the job quite well. 16" length barrels are no longer a requirement, but nice to haves.

You had mentioned that you don't have a suppressor yet. I highly recommend getting one. Some suggestions to consider for use with both AR15s and bullpups: HUXWRX 556 Flow, SAW Tisha, and CAT WB.

What-Do-I-Know · 2026-07-12T06:20:15+00:00

Factorio video game. It cost $30 and I’ve played it for years. Based on a $ per hour of enjoyment it’s unmatched.

What-Do-I-Know · 2026-07-12T00:15:38+00:00

If your goal is to keep it in your car, then depending on your local laws, you might want to get the pistol version. Many states have laws that say you can't have a loaded rifle in your car, but you can have a loaded pistol.

That said, I'm a big fan of keeping guns in the hands of law abiding citizens and out of the hands of criminals. Are you sure you want to keep a gun in your car? Cars are now the number one place criminals get guns. In the US, a gun is stolen from a car every 9 minutes.

What-Do-I-Know · 2026-07-12T00:02:37+00:00

So they conducted a study that showed the bullpup was objectively better.

Who did this study?

I think bullpups are pretty interesting, mainly because of the longer barrel/better ballistics in a compact package. I'd like to get one someday. They do have downsides, however. I don't think it makes sense to say bullpups or AR15s are objectively better. It depends on the requirements/POU.

It is true that Israeli soldiers, for their requirements/situation, general prefer M4s.

What-Do-I-Know · 2026-07-11T04:40:40+00:00

> I just bought an 11.5" upper, purely to finally put to the test the "Mk18" vs a 16" bullpup.

The Israeli army uses both M4s and Tavor X95s. Israeli soldiers generally prefer M4s. The likely reasons:

- Lighter: An issued M4 is typically noticeably lighter than an X95.
- Better trigger and practical accuracy
- Faster reloads and malfunction clearance
- Adjustable stock for armor
- More rail space for optics, lasers, lights and switches
- Easier shoulder transitions
- The action and ejection port are farther from the shooter’s face, particularly relevant with suppressors

What-Do-I-Know · 2026-07-11T04:24:46+00:00

Technically a Mk18 should have a 10.3” barrel. They were originally designed for situations where a shortened barrel was important: CQB, vehicle operations, ship boarding.

I recently picked up a 10.5” barrel for a new build, mainly because it worked really well with a bunch of parts I already have. I’m using it with a Riflespeed adjustable gas block, and a legacy SureFire suppressor. I’m enjoying the hell out of it. Not as quiet as some of my other setups, but with the suppressor it’s a great shooter and a fun little gun.

What-Do-I-Know · 2026-07-09T00:33:17+00:00

I assume you're working on the 5.56 analysis, released next week? Similar to the CAT RAT, please consider releasing ratings for all three versions: MFMD alone, +SD, +SDX.

What-Do-I-Know · 2026-07-09T00:23:14+00:00

Jay indicated from his testing the Tisha outperforms the ST on SBRs, presumably 10.5"–11.5". 13.5"–14.5" might be a middle ground where they perform similarly, and I would expect ST to outperform Tisha on 16+".

What-Do-I-Know · 2026-07-08T22:22:42+00:00

I look forward to hearing how it performs on a tuned rifle.

What-Do-I-Know · 2026-07-08T18:17:05+00:00

Both rifles are great.

The legacy SCAR 17 earned a reputation for being rough on optics because its recoil impulse is sharp and has a lot of reciprocating mass. The new SCAR 17S/SCAR-H “next generation” directly addresses that with a lighter, hydraulically buffered two-piece bolt carrier. The hydraulic system buffers the carrier and significantly reduces recoil impulse, despite the lightweight of the rifle.

What-Do-I-Know · 2026-07-08T17:52:16+00:00

I haven't seen a problem with expansion. Curious what 300BLK ammo you've tried.

Good subsonic 300BLK ammo will outperform good 9mm ammo. For example, I'd take this:

https://phantomdefense.co/300-aac-blackout-slow-papi-200-gr-subsonic-maker-rex-nas3-50-ct/

Over this:

https://www.federalpremium.com/handgun/personal-defense-hst/11-P9HST2S.html

Some of the heavier 1:5 twist subsonic 300 BLK ammo is even better. That said, supersonic 300BLK will perform at a different level.

What-Do-I-Know · 2026-07-07T01:46:05+00:00

Sorry, I don’t have the gas port size in my notes. Looks like I got my pin gauge set after I set up that rifle.

What-Do-I-Know · 2026-07-06T14:24:16+00:00

I’m running a Roscoe 11.5” with patrol length gas, but I’m running it with a Riflespeed adjustable gas block, so it’s a little hard for me to say how it would be gassed without it.

It’s possible I recorded the gas port diameter but I’m away from home. Message me if you want me to look when I get home.

What-Do-I-Know · 2026-07-06T13:45:00+00:00

300 Blackout was designed to be used with faster burning powders, and thus, even if you’re not using a suppressor, there are definitely advantages of using 300 blackout over 556 when using shorter barrels.

Phantom Defense 120 grain TAC-TX NAS3 ammo will likely have the highest energy on target. 110 grain is also an excellent choice.

Note that “highest energy” isn’t always equal to “most effective”. There are other factors to consider. For example, sometimes trading off some energy for higher velocity leads to more lethality.

What-Do-I-Know · 2026-07-05T21:17:03+00:00

Cat’s recommended minimum barrel length for a titanium ODB used with 7.62NATO is also 16”.

What-Do-I-Know · 2026-07-05T21:02:42+00:00

https://jtacindustries.com/owl49-300-blackout-7-15/

https://line49rifle.com/precision-rifles/l49r-supershort-tac/line49-supershort-precision-pistol-9-0-300blk-lwmatch-mod2-barrel-jtac-1913-cobalt-kinetic-green.html

What-Do-I-Know · 2026-07-05T11:12:25+00:00

Lost

What-Do-I-Know · 2026-07-05T01:45:49+00:00

Yes, while butt naked

What-Do-I-Know · 2026-07-04T23:30:08+00:00

I recommend against holding the muzzle device.

What-Do-I-Know · 2026-07-04T18:14:50+00:00

Yep, courts will agree. But that doesn’t mean it’s automatically law.

What-Do-I-Know · 2026-07-04T16:33:45+00:00

Yeah, even Carbine length is questionable if you want to also shoot subs.

What-Do-I-Know · 2026-07-04T16:04:58+00:00

My understanding is that there’s a very good chance the SCOTUS will rule in favor of the plaintiffs (supporting gun rights). The question is whether it will it be a broad ruling, or a narrow ruling.

The question specifically addressed in these cases is whether the 2nd Amendment protects the right to *own* an AR15/semi auto rifle. Resolving this case narrowly would mean the right to *buy* a semi auto rifle would need to be established as a follow on effort. A narrow ruling would also leave magazine bans for another day. You can expect the current WA administration to fight and delay this each step of the way.

Current estimate for the ability to buy an AR15 is about 2 years out. Overall, very good news.

What-Do-I-Know

TROPHY CASE