Is DonnyFL Ronin worth while upgrade from FX moderator on impact 25 factory tune

I stumbled across this when looking for silencer information some time back. It has comparisons on quite a few moderators including the two you are after. Lots of scrolling and reading involved.

https://www.silentthunderordnance.com/blog/2019/3/1/airgun-moderator-design-performance-and-development-the-big-test-part-5

Aloha,

I also agree with biohazardman, STO gladius moderator is the quietest in my collection. 
Aloha, 

Keone

Avoid the STO moderators. STO told me they could handle 80FPE, but the Mus and Pilum (both "moderate flow") couldn't handle 50-60FPE and they fell apart on me quickly. I ran the Mus for a day and noticed the foam started coming into the bore path., but it turned out not to be the case. When I contacted him about the problems that I was having, he immediately accused me of being at fault

There is a reason why DonnyFL, TKO, and others have had success. The Sumo and Ronin are as quiet as the big Mus was. The Pilum is narrower, comparable to a Sumo without the durability factors.

I also had a very negative experience with STO. 

I contacted them regarding a moderator for a .30 leshiy build and after they asked me a couple of technical questions that I couldn’t answer they told me they wouldn’t sell one to me.

i went back and forth a couple of times but they were what I thought very rude about it and then just chose to ignore me. I am only sharing my experience. Good luck with your choice.

I put a Tanto on mine and it works fine. Quiet as can be.

I just got a Sumo for my .30 cal. Impact and it made quite a difference. It's only an inch longer then the Donnyfl that came with the Impact.

i also have a tanto on my .25 impact. I don't know if there is any different' s from factory caps . 

Sounds the same to me. 

Avoid the STO moderators. STO told me they could handle 80FPE, but the Mus and Pilum (both "moderate flow") couldn't handle 50-60FPE and they fell apart on me quickly. I ran the Mus for a day and noticed the foam started coming into the bore path., but it turned out not to be the case. When I contacted him about the problems that I was having, he immediately accused me of being at fault

There is a reason why DonnyFL, TKO, and others have had success. The Sumo and Ronin are as quiet as the big Mus was. The Pilum is narrower, comparable to a Sumo without the durability factors.

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I am using the Gladius at 80FPE and it is fine thus far with a few hundred rounds down range. My Pilum is werqing well in the 30-40FPE with several hundred rounds through it. I just thought that the Pilum was a bit small for 80FPE guess I was correct in that thought. But the Mus is larger than the Gadius so should not die prematurely with 80fpe. STO should not be recommending units in the moderate flow if they won't take it. Thanks for the information.

Edit; Fergot I recently tuned down to 74fpe to save air.

Very interesting, according to his test the bigger ronin is louder than my FX? Is the test data for sound in DB? 


Edit: google found the page to buy them, their website is rather interesting and a bit confusing. According to their test the Pilum is the quietest? Which one should I get? 


also saw a posting on AGN that 2 STO moderators fell apart? Any else has durability issues?

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The test data is not in DB.

Good choice. I pleaded with the guy who makes STO moderators in his thread to use Decibels as a unit of measuring sound being its universally accepted and understood quite easily...but of course those readings wouldn't likely be in his moderators favor so he markets them in a way that does...its quite shameless and a blatant misrepresentation of the product hes offering. I lost all interest in his research proceeding this because any 'sound engineer' would know better than anyone that you want a full 25hz- 7khz fasted weighed measurement in DB that told you what frequencies the moderator hit, and at what decibel level...simple.

To my ear, there is an appreciable difference between a Ronin and an STO Mus, both in terms of volume and tone. For reference, this is shooting 61 ftl bs in .25. 

The Mus is also significantly lighter.

I have had several dealings with STO, and the communication and duty of care are quite remarkable.

Avoid the STO moderators. STO told me they could handle 80FPE, but the Mus and Pilum (both "moderate flow") couldn't handle 50-60FPE and they fell apart on me quickly. I ran the Mus for a day and noticed the foam started coming into the bore path., but it turned out not to be the case. When I contacted him about the problems that I was having, he immediately accused me of being at fault

There is a reason why DonnyFL, TKO, and others have had success. The Sumo and Ronin are as quiet as the big Mus was. The Pilum is narrower, comparable to a Sumo without the durability factors.

Click to expand...

My Gladius exploded on me yesterday. I had only put 25 or 30 shots through it. My gun is a .25 Condor that is regulated. It's making 80 FPE, which STO does indeed reference on his website as it pertains to a .30 FX Impact. I have pictures of the left over pieces. I pulled the trigger, heard a very loud explosion, and watched the end cap and 2/3 of the 3D printed internals fly 30 yards downrange. I contacted STO and explained to him the situation. He told me he doesn't think it's a moderator failure. He thinks it's an issue with my gun. He asked me if my barrel was threaded, or if I was using an adapter to affix the moderator to my rifle. I told him the barrel was threaded, but if he's insinuating it may have shaken apart because of harmonics, he was incorrect. My rifle is built around the Condor SS frame, and I have 4 barrel baffles evenly distributed throughout the frame of the gun that concentrically hold the barrel within the frame of the rifle. The sole purpose of these is to eliminate harmonics. I'm still waiting to hear back. He told me I could return the moderator and he would send me another one (shipping paid at my cost of course). But when he theorizes or proposes that the failure was due to the gun and not the moderator itself, it relinquished him from accountability if it happens again. 

When I look at the extrusions from the 3D printing (which are impossible to see unless the moderator blows apart because it's all epoxied together) I can see hollow portions in the middle of sections that should be solid. I will attach pictures for everyone to see. I want the moderator to work SO BADLY because it's very quiet and it's as light as a feather. But when my neighbor calls me minutes after the failure, and he tells me he not only heard the explosion when the moderator failed, but he also heard the slug "whistle" by his property as it probably spun off in some random direction at 960 fps, that's a VERY DANGEROUS failure. 

I'm speculating he's going to suggest it's a harmonics issue. I've read his research on various items, and he is a very brilliant guy. I'm going to give him the benefit of the doubt for now and I'm genuinely interested in his thought about why he thinks the failure took place. I'm not here to demonize him or his product. If it's something I did wrong, I'm definitely open to hear what he has to say. 

MtnGhost- describe the platform you had the moderator attached to. Are you attaching it to a threaded barrel, or a threaded barrel adapter? I'm still perplexed why this would matter, but this is what he specifically asked me. So I sent him a picture of my barrel per his request. There is zero evidence of clipping, and he even admitted that he doesn't think that clipping is the issue. He has a statement on his website that the moderators are all made to order and they are still in an experimental stage. 

Here are the pictures of the failure:

Just hoping mine does not do that I have a couple hundred rounds through it so far so possibly it has a chance of lasting? Looks like a manufacturing defect to me. Material or temperature used when printing could well be the problem. Hope he realizes he has a problem and gets it figured cuz his moderators are excellent units weight and noise wise.

Edit; I was shooting at 80fpe but recently tuned down to 74fpe to save some air it should be slightly easier on the Gladius.

He corresponded with me via email. He actually made a VERY valuable point. I think he's probably right. Let me quote what he said. Give it a read and give me your thoughts:

"So my hypothesis was quite simple: you put a moderate flow moderator on a high flow rifle. So far what you've said has suggested that is correct. A little reading is necessary to understand this, but if you click on the link at the bottom of the "flow" explanation of the moderator, you'll find a link to a page which explains it (and how to properly select a moderator for a given rifle). In short FPE is just a very rough way to estimate air output of an airgun, and is far from the only factor to consider. The absence of a shroud combined with a high barrel drag projectile (slug) and probably an inefficient rifle (Airforce rifles are notoriously air-inefficient) means you're putting out substantially more air than the nominally 80FPE test platform and there is significantly less air volume where that pressure can be dissipated (FX Crown .30). Think about where those gas diodes can store all that air? In a direct-thread gun, all you get is the barrel bore itself. This puts much more load on the core than it was ever designed and tested for. It has been on my to-do list to develop a core for a high flow rifle at some point, but finding a suitable test platform has proven difficult. The AAA Slayer I borrowed was both unregulated, so shot-to-shot variation made comparisons very difficult, and mechanically the rifle itself was way too loud anyway. But I digress. Point is, if you do some quick napkin math with the ideal gas law and a few conservative assumptions about your rifle, you put roughly an order of magnitude more pressure in the moderator than it was rated for. 

Anyway the best way to proceed from here is for me to take a look at the core and make sure nothing was defective about it and/or nothing else went wrong with your system. If you simply over-pressured it, the best move is probably to just give you a refund. Your condor is probably pushing cores into a power range I've simply not got a good test rig for, so even if they could physically survive, it isn't going to be optimized to perform well."

What he says makes sense to me. AF air rifles are capable of extreme power. Even regulated versions. I appreciated his honesty. I hope he comes out with a high power version because the design is brilliant. But at this point, I think I'm just over-pressurizing the regulator. I've tried to tune my gun to be efficient with air, but it's difficult with the AF platform.