When people ask me which DonnyFL moderator to put on a .357, the answer most of the time is the Ronin, and the reason comes down to volume. A big bore pushes a lot of air out the muzzle on every shot, and a moderator has to have enough internal space to slow that air down before it leaves, which is something a small can simply cannot do no matter how well it is made. The Ronin is big, bold and designed to impress, and in this Field Notes post I want to explain how to pick the right Ronin for a .357, which adapter gets it onto your gun, and when it makes sense to add the Extender.
The DonnyFL Ronin, our 2 x 6.25 inch moderator available in .22/.25, .30, .357 and .50.
Quick Summary
- The moderator: DonnyFL Ronin, 2 x 6.25 inches, about 10.4 oz, mono-core, pre-wrapped in felt, ships in a protective red tube.
- Calibers: .22/.25, .30, .357 and .50, with rear caps in 1/2 x 20 UNF, big bore M18x1, M14x1.25 and FX M20x1.
- .357 adapters: Benjamin Bulldog, Ataman M2R .357 and the Hatsan Blitz.
- More quiet: the Emperor/Ronin Extender adds a 6.25 inch expansion chamber to the latest Ronin with grooves in the front cap.
- Maintenance: apart in under 10 seconds with no hex key or torch.
Why the Ronin Works on Big Bores
The Ronin is 2 inches in diameter and 6.25 inches long and weighs around 10.4 ounces. That 2 inch tube is the important number, because it gives the Ronin a much larger internal volume than our 1.6 inch moderators, and on a .357 that volume is exactly what you need. We will be honest that it may be overkill on .177 and .22, but on the bigger calibers it looks incredibly awesome and performs exceptionally well.
Like the rest of the line it uses a mono-core design, which keeps the path through the moderator concentric and limits the chance of a projectile clipping, and that matters even more with heavy .357 slugs where a clip is not something you want to experience. There are no moving parts and no epoxy that can work loose after thousands of rounds, it is precision CNC machined, sandblasted and anodized, and it comes pre-wrapped in felt.
The latest Ronin has grooves in the front cap, which is how you know it works with the Extender and the newer endcaps.
The Ronin also has real competition history behind it. Keith Gibson won the benchrest division at RMAC 2022 running a Ronin, which is a good reminder that a big moderator and precision are not at odds with each other when the moderator is built straight.
Choosing the Caliber and Rear Cap
Caliber
The Ronin comes in .22/.25, .30, .357 and .50 sizes. For a .357 you want the .357 Ronin, and if you shoot a .30 that pushes a lot of air you can treat the .357 as your one size up when you are mounting to a shroud, which is the same sizing rule we use across the whole DonnyFL line.
Rear cap threads
Rear caps are available in 1/2 x 20 UNF, big bore M18x1, M14x1.25 and FX M20x1. Most .357 rifles and the DonnyFL big bore adapters finish in M18x1, so that is the cap most big bore owners end up with. If you move the Ronin to a different gun later, the Ronin/Emperor Endcaps let you swap the rear cap instead of buying a new moderator, as long as you have the latest model with the grooves in the front cap.
Big Bore Adapters That Pair With the Ronin
Benjamin .357 Bulldog
The .357 Bulldog has become very popular for big game hunting, and the A41 adapter is designed to go back to the barrel and slide over the barrel bushing, which keeps the barrel aligned with the adapter's exit hole. The factory gun already includes that bushing. On the Bulldog I recommend at minimum the .357 Ronin, because the .357 FX suppressor is not enough to quiet this gun down. If you choose an Emperor for the Bulldog instead, do not add the Extender, because the extra weight hanging on the adapter can cause precision problems.
The Bulldog A41 slides over the barrel bushing to keep the barrel aligned with the exit hole.
Ataman M2R .357
For the Ataman M2R in .357, the A27 adapter gives you M18x1 threads. It is CNC machined from 6061 T6 aluminum with a matte black anodize and diamond pattern knurling for an easy grip, and it is specific to the .357 model.
Hatsan Blitz
The Hatsan Blitz is an M18x1 adapter that has been improved for more air flow and is compatible up to .30 caliber. We recommend the S20A Ronin on this gun, and it has worked flawlessly on our own setup. Results can vary, and some guns may need a small modification to run properly in semi-auto mode. The Blitz is similar to the Bullmaster, and others have fixed magazine indexing by replacing the spring with a lighter one from the hardware store, which is the same fix we used on ours.
When to Add the Emperor/Ronin Extender
If your Ronin is still louder than you would like, the Emperor/Ronin Extender quiets things down even more. It is a 6.25 inch expansion chamber that attaches to the rear of the moderator and increases the air volume captured inside, which results in noticeably quieter shots. It works with the Emperor v3 and the latest Ronin models with grooves in the front cap, and you can thread it to your gun with the Endcaps for the Ronin/Emperor Extender.
Keep in mind that expansion chambers do not contain internal baffles, so the Extender adds volume rather than more baffle stack, and it adds length and weight out at the muzzle. On a rifle with a solid barrel mount and a stout adapter that is not a problem, but as we noted on the Bulldog, weight hanging on an adapter that only slides over a bushing is something to respect.
The Emperor/Ronin Extender adds a 6.25 inch expansion chamber with no internal baffles.
Shop the Emperor/Ronin Extender
Keeping a Big Bore Moderator Healthy
Big bores leave more lube and debris behind than small calibers, so it pays to pull the Ronin apart now and then. It comes apart in less than 10 seconds by unscrewing the rear end cap and pushing back the mono-core, with no hex key or torch required, and you can re-wrap the inner tube with different sound absorbing materials if you want to experiment with the dampening.
Ronin Big Bore Checklist
Choose the .357 Ronin for a .357, and size up when mounting to a shroud.
Match the rear cap to your adapter, usually M18x1 on big bores.
Do not hang an Extender on the Bulldog with an Emperor.
Use the red storage tube for transport, and remember ribbed endcaps will not fit inside it.
Frequently Asked Questions
What size is the DonnyFL Ronin?
The Ronin is 2 inches in diameter and 6.25 inches long and weighs around 10.4 oz. It comes in .22/.25, .30, .357 and .50 calibers.
Which Ronin rear cap do I need for a .357?
Most .357 airguns and DonnyFL big bore adapters use M18x1 threads, so the big bore M18x1 rear cap is the most common choice. Caps are also available in 1/2 x 20 UNF, M14x1.25 and FX M20x1.
Is the Ronin quiet enough for a Benjamin Bulldog?
We recommend at minimum the .357 Ronin on the Bulldog, using the A41 adapter, because the .357 FX suppressor is not enough to quiet that gun down.
Does the Emperor/Ronin Extender fit my Ronin?
It fits the latest Ronin models with grooves in the front cap, along with the Emperor v3. It adds a 6.25 inch expansion chamber with no internal baffles.
Which Ronin should I run on the Hatsan Blitz?
We recommend the S20A Ronin on the Blitz with the A117 M18x1 adapter. Semi-auto cycling can vary, and a lighter magazine spring has fixed indexing issues for us and others.
How do I clean the Ronin?
Unscrew the rear end cap and push back the mono-core. It comes apart in under 10 seconds with no tools, and you can re-wrap the inner tube with felt or other sound absorbing materials.
Final Thoughts
A .357 is a serious airgun, and it deserves a moderator with enough volume to actually tame it. The Ronin gives you that volume in a precision built mono-core package, the right adapter gets it on straight, and the Extender is there when you want to take it further. Get those three things right and your big bore becomes a much more pleasant rifle to shoot and to hunt with.
