Crosman 451 Hammer saga: Part 1

Canadian World of Replica Air Pistols reader R-Gun Pete recently added a vintage Crosman 451 to his already vast collection of replica pistols. Like many 451 owners, he was concerned about the fragile sintered steel hammer which has been known to break. R-Gun Pete has a background in engineering and access to milling and cutting equipment so he decided to make a replacement hammer in steel so that he could enjoy shooting the 451 without worrying about the possibility of the hammer breaking. However, this turned out to be more challenging than might have been anticipated. The saga starts here…

R-Gun Pete tells the story:

I had read about the Crosman 451, but living in Canada, I estimated the chance of ever seeing one available for sale was not very high. So when I came unexpectedly across one in June 2016 I bought it.


Knowing that there was a design weakness with the sintered metal hammer and considering my background I decided to use part of my summer annual leave to make a new hammer for it. Having a sturdier replacement would allow me to enjoy the airgun without worrying that its collectible value could be ruined by a broken part.

This was the beginning of the hammer saga which required several iterations before I was able to reach a positive outcome.


After buying the Crosman 451, the next important step was to find the Factory Service Manual and this proved fairly difficult. Most of the other models have their manuals available for free somewhere on the internet but not the 451 (the 622 was another difficult one to get and I ended up buying it).

During my research, I found several eBay sellers from the U.S. who had copies but they wouldn’t ship to Canada except for one who was on vacation until late Fall (which was a bit late for my plan). In despair, I contacted a lot of different people (practically around the world) including Steve who unfortunately didn’t have it but asked me to keep in touch if, eventually, I was able to tackle my project.

In the meantime I bought a vintage air rifle from Mr. Marvin (Airgun Oldies) and as a last attempt I  checked with him if, by any chance, he would have a copy of it. Miraculously he had the Factory Service Manual for the Crosman 451 so he kindly scanned it and sent it by email.

The project was now back on track and I was planning to try to make a new hammer during my vacation in August 2016. Before going any further, I should stop to give you some information on my background and motivations.

I was born in a francophone area of Montreal (Quebec) in the mid-fifties. In the sixties, I grew up with cowboy movies, police shows and war movies (the same as a lot of other peoples of my age). At the time, my preferred toys were cap guns but I also liked to read and watch movies. During those days my dream was to have a private screening room and a private shooting range when I was an adult.

In some ways, I have now quasi fulfilled both dreams as I have a large collection of DVDs and Blu-ray movies as well as a large collection of airguns. They are not the actual things but that is close enough for me.

When I was a teenager, English was not my forte. In class, if I could have hidden under my desk to avoid answering questions, I would have done so. Later in life it would change.

In the 70’s, about the time I was in college, it was not clearly evident where to go to buy airguns. Canadian Tire (sort of automotive/hardware store in Canada) was an easy place to find some and I bought a cowboy air pistol. It was not working very well and was very weak so I returned it. Now that I am a collector I regret it (at the time I had no idea that I would become one several years down the road). At some point later, I found an RO72, once again it was not a very good pistol but at least it was working so I kept it (and still have it). Technically, this was my first pellet gun.

After graduating from College, I started my career as a Graphic Artist and Illustrator. I worked in advertising for several publicity agencies and studios over a period of more than 15 years (there were even a few Anglophone agencies in the lot, my English was bad but I was able to get along).

Later I moved to Kingston (Ontario) with my wife after she was hired as a University professor. This move lead to a change of career for me, I got recycled from a Graphic Artist to a Technical Draughtsman.


Being in an Anglophone environment my English had a chance to improve. Over two decades and a half, my job also evolved from Draughtsman to CAD instructor and finally CAM instructor (CNC milling). This combination makes for an interesting mix that is (practically) never boring. The interaction with students is really fun and the research projects are really challenging so this makes for a very satisfying job. Nevertheless retirement is approaching in a few years and it is time to start training some young pup to take over.

The computer is a great tool to prepare exam question. In the CAD software the model part is linked to the drawing and it is easy to have question and answer that match together. The students are still required to sketch by hand according to different types of projection such as orthographic, isometric or oblique.

Oblique views were a type of projection that was popular when drafting was entirely done by hand. All the details from the front view were actual shapes and sizes. This meant that circles were still circles instead of being transformed into ellipses and it is a lot easier to draw a circle with a compass than an ellipse. The receding lines were made half the original length at standard angles of 30, 45 or 60 degrees. CAD software cannot produce automatically this type of projection so I was experimenting if I could find a way to make it happen. The following picture is one of these experiments done with one of my favorite subjects (in this case it is an airsoft pistol).


Going from my teenage years into adulthood, the same thing happened to me as to a lot of other peoples, the interest in guns of all sorts got on the back burner once girls, jobs and cars took the front scene. Wife, kids and limited available money meant that it stayed on the back burner a bit longer but eventually the flame got rekindled.

In 1997, when I decided to buy an airgun, I still didn’t know that I would eventually become a collector. I just wanted a pistol to plink in my garage. Again Canadian Tire had been my source. I bought a Crosman AutoAir II which replicates an AMT Automag II. This was a dreadful pistol; just thinking of it is enough to make my trigger finger hurt.

My next one was a Crosman 1008 (S&W third generation) which was a better shooter, followed by a Crosman 357 (4” and 8” barrels) looking like a Colt Python.

Later I discovered the Army Surplus Store. The place had been a great source of Tokyo Marui airsoft springers until the Canadian government spoiled the fun with Replica Legislation in December 1998.

Because I could order more exotic products (CO2 pellet replicas were still legal) through them, it gave me more options than the Canadian Tire store. After several years, it begun to feel that the Army Surplus Store was too slow to get my special orders in so I started exploring the Internet. This really expanded my horizons and gave me access to products I couldn’t get before. This meant access to new airgun products just released in Canada, more powerful airsoft pistols and also replica paintball guns (RAM or Real Action Markers).

I have never been a tinkerer in my youth. Some people like to take thing apart but for me if it is not broken I leave it alone. Since I started my new career I slowly developed the skills to better understand working mechanisms.

The Real Action Markers are really finicky beasts. They have all sorts of problems and the seller was in Alberta so shipping back and forth would turn up to be expensive. This is what got me interested in airgunsmithing. It was possible to have training but it would be offered only on location at the seller’s place. Considering the cost of the course, travel, accommodations plus time off work it was adding up to be too much. Instead I decided to experiment on my sick marker. Either way, I would fix or I would break it but for sure I would learn something and all that for just the price of the marker (which would end up being a fraction of the training cost anyway). I developed a relationship with the seller and he answered my questions so when the marker was fixed, in return for his help, I prepared a repair guide that he could give to other customers. The following picture was a sample of the type of questions I sent him.


I am a strange breed of collector. Some people will focus on one pistol and collect all the variants but I went the opposite way: I decided from that point that I would like to assemble a collection that will recreate the history of firearms from black powder to modern pistols without using actual firearms.

However, some of my airguns are not replicas so they are in another type of collection. This time I was trying to cover a whole range of mechanical systems: Break Barrel, Spring Piston, Single Stroke Pneumatic, Multi-Pump and PCP. These include:

RO72 (1973-1994) Gun Toy from Milan Italy,
Model HB-22 (1991-) and EB-22 (1992-) Benjamin / Crosman Corp – USA,
Model 150 (1956-1967) Crosman Corp – USA,
Model 2289G Backpacker (1998-) Crosman – USA,
Model 1377 American Classic (1998-) Crosman – USA,
Model 2240 (1999-) Crosman Corp – USA,
WEBLEY JUNIOR (1929-1938) Webley & Scott – England,
HURRICANE (1977-2005) Webley & Scott – England,
TEMPEST (variant II 1981-2005) Webley & Scott – England,
MODEL 2004 DELUXE (2005-2006) Marksman – USA,
Gamo Compact Target – Spain
Air Arms Alfa-Sport Competition PCP (to be determined but in the 90’s) – Czech Republic.
Cometa Indian – Spain
Daisy Model  717  – USA
Brococks Atomic Super 6  and Grand Prix Super 6 – England
1701P Crosman Silhouette –  USA
Baikal IZH-46M – Russia

Through a mixture of pellet guns, BB guns, airsoft guns, paintball markers, RAM’s (Real Action Marker), Flare Blank guns and non-firing replicas, I was able to cover from the 18th century to the beginning of the 21st century.

In 2013, I thought that my collection was complete because I was running out of space in the storage cabinets that I owned and it was out of question to buy more gun safes.

The pictures below will give you an idea of what was my intent but at the same time I must tell you that it is not complete as mentioned previously. I made a liar of myself. Between 2013 and 2016 I bought several new airguns.

Without acquiring any new storage cabinet, it seems that I was able to be creative with 3D space. By making a more efficient use of space I opened up room for my new toys. Unfortunately they won’t appear in the following compilation as this is the 2013 collection. I hope to be able to update it once I am retired and this time it is true that I am running out of space.










Now that the introduction is out of the way it is time to return to the topic of interest.

Before I disassembled the 451 for the first time, I carefully studied the instructions and tried to relate each of the steps and parts in the written instruction with the part number shown on the list. As it was a bit confusing, I used color codes to keep track of groups.


After doing the disassembly/reassembly routine a fair amount of times in the course of solving the reverse engineering of the hammer, I realized that the procedure is in fact simpler than trying to read the written instructions.

One picture is worth 1000 words…  How true it is. You will see in the next pictures.








The sintered steel hammer once removed from the pistol was measured with a caliper. It is not the best way to reverse engineer a part but this is the equipment I have at home.

Whenever I have to repair an airgun, I am trying to do it with what is readily available instead of relying on specialized kit.

These kits can be easy to obtain now but could become unavailable in the future so if I can already find a viable alternative this is my preferred route.

My goal is to replicate the hammer with really basic means: band saw, drill press,  dremel tool and files.

The holes are two sizes 1/8” (.125) and 3/16” (.1875).


The thickness of the core is about ¼ inch and the head is ½ inch and there is a 3/8 inch long spring pin. The way to simplify the artisanal fabrication is to think in term of 2D shapes.


From the dimensions taken on the part a CAD model was made, the intent is to use it to print a template.

As could be seen on the screen there will be a contour for the hammer core and to widen the head two small plates will be stuck on each side. I am planning to use 3/32” spring pins to hold the pieces together.


After looking in my box of scrap pieces that I scavenged from the shop at work, I found that I had several good candidates for my need. Those were broken samples from a stretching test. As they are exactly .125”, I can sandwich 2 plates together to make the core and 4 plates are thick enough for the head.


After printing the template and gluing it on the plates sandwiched with double face tape, the first step was to drill the holes and to place some pins to hold them together. I also had enough room to also place the shape of the head and once cut it will give me the two small pieces that are needed.


This completes the preparation of the job. In the next installment we will see the result of the first try.

R-Gun Pete

Related Pages

Crosman 451 review

Crosman 451 Hammer saga: Part 2

Crosman 451 Hammer saga: Part 3

Crosman 451 Hammer saga: Part 4

Crosman 451 Hammer Saga: Part 5

Crosman 451 Hammer saga: Part 6

Crosman 451 Hammer saga: Part 7

Crosman 451 Hammer saga: Part 8

Technical articles



Marvin The Air Gun Guy (Airgun Oldies)

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