Benjamin Marauder Tuning – The Thing (Almost) All People Do Wrong!

Benjamin Marauder tuning. Just about all owners do this to their air rifle. They’re all looking for more power from the Marauder. But – amazingly – almost all people do it wrong and end-up with less power than they could have!

Why is this and how do we know? I’ll explain…

Archer Airguns Inc. (the owner of Hard Air Magazine) offers an airgun repair service. We specialize in repairing and tuning Marauder air rifles. This means that we have seen inside many hundreds of Marauders from owners all across the country over many years.

When we dismantle the gun for repair, we can see if – and how – the owner has tuned his or her air rifle.

This is how we know that close to 100% of all Marauder owners try to tune their gun for more power. Also we can see that more than 75% make one simple mistake that results in lower power than could have been obtained.

NOTE. Safety First! Do not make any changes to your air rifle – including tuning – until you have first proved the gun “clear” and then released all air pressure by using a “degassing key” or by shooting the gun until it will fire no more.

Benjamin Marauder Tuning Options

The Marauder air rifle was one of the earliest PCPs to offer its owners the ability to change its performance characteristics. It’s possible to adjust performance in three ways.
1. Adjusting the Transfer Port aperture in the valve.
2. Altering the hammer spring tension.
3. Varying the striker length.

Here we can see how these parts of the gun fit together.

Benjamin Marauder Tuning Options – Hammer Spring

The thing that we find almost inevitably is that Marauder owners increase tension on the hammer spring.

This is done by rotating the hammer spring guide clockwise using a 1/4-Inch Allen (hex) wrench inserted through the tube end cap.

The greater spring tension helps the hammer to hit the valve harder and for longer. This allows more High Pressure Air to be released with each shot. The result is increased Muzzle Velocity (although for a lower number of shots).

Benjamin Marauder Tuning Options – Transfer Port

This option is – in my opinion – the most beneficial option for increasing the power of the Marauder. Yet it seems to be done relatively little…

The Transfer Port adjustment screw is accessed from the outside of the gun. Although this adjustment may be made with the stock in place, it’s usually easier to do with the stock removed.

The Transfer Port is a hole in the valve through which the air passes when the gun is fired. In the Marauder, the size of this hole is constricted by a screw within the valve.

That screw is retained in place by means of a jam screw. The jam screw must be removed first before adjusting the Transfer Port screw.

The further “out” (counter-clockwise) the Transfer Port screw is turned, the less it restricts the opening. This allows the air to escape faster when the trigger is pulled and thus provides increased power.

Here it’s important to stress that the Transfer Port screw must not be completely removed from the valve. This would be a disaster as the High Pressure Air would exhaust there rather than through the barrel!

About 4 1/2 turns from “right in” is required to open the Transfer Port screw completely. Not more! Don’t forget to replace the jam screw afterwards. Both need a 5/64-Inch Allen (hex) key for operation.

Benjamin Marauder Tuning Options – Striker

So this is where things usually go wrong! The striker is a part that effectively changes the length of the Hammer Assembly. In fact, it’s a flat-headed screw that is retained in the front of the hammer itself.

In the Marauder air rifle, it’s adjusted using a 1/8-Inch Allen (hex) key inserted through the end of the tube end cap. This is the end-on view from the rear of the hammer.

As the striker is rotated, it can project more or less from the hammer, as is shown in the photograph below. Just about all our sample of Marauder owners also adjust the striker length.

Page 7 (in English) of the Marauder Owner’s Manual explains what to do. Here it is…

So it’s clearly explained that having the striker right “out”, ie at maximum extension, will give the greatest hammer energy and thus power. Of course, that’s what most people want.

However, where things obviously go wrong is that increased striker extension is obtained by rotating the striker counter-clockwise.

Yes, it says this in the owner’s manual, but it’s clear that most owners naturally rotate the striker clockwise. We know this as most Marauder air rifles we repair have a fully compressed hammer spring, yet a fully-retracted striker.

In other words, the owners have rotated the striker clockwise by mistake. The result is that the power increase gained by increasing the hammer spring tension will have been lost through shortening the striker. Aaaaaggggghhhhh!!!!!

Incidentally, this also proves that most owners do not possess a Chronograph. Using one while testing will easily show this result.

Now I’m sure that you will not have made this error in your Benjamin Marauder tuning. But maybe it would be best to double-check…

Shameless Plug!

Actually, the best way to obtain more power from your Benjamin Marauder air rifle is to install the Archer Airguns Tune Kit For Benjamin Marauder Air Rifles. It really works!

This provides the parts and – most important – information you need to obtain the best power from your Marauder, while still retaining a decent shot count.

You can read more about this Tune kit in these HAM posts:
1. Add 100 FPS.
2. More test results.
3. Theory of operation.