Crosman Mark-I - Packaging Variations.
Courtesy of Leonardj.
Earlier boxes were made of card stock, with a lift off removable lid. The lid remained the same for this series of box, but the internal liner underwent minor changes, such as the elimination of the courtesy powerlet, and it's corresponding cutout.
The next style of box was made from corrugated cardboard, with a flip open lid, hinged at the rear of the box.
The last of the box styles returned to a lift off lid of corrugated cardboard construction, but the lower portion of the box was replaced by a fitted styrofoam tray.
Crosman Mark-I - Article by Todd Cooper.
Thank you to Todd Cooper for permission to post this excellent article.
Crosman Mark I and Mark II Air Pistols
By Todd Cooper
The 40 year old Crosman Mark I/II design still enjoys wide spread popularity in the American-Canadian airgun community, even though the pistol has been out of production for over 20 years. There are many reasons for the strong desire for this classic air pistol.
Here is a quick list of 10 desirable features of the Mark pistol:
1 - Solid construction with a good balance;
2 - Comfortable grip with large thumbrest;
3 - Crisp two stage adjustable trigger (approx 1-3 lb range);
4 - Good accuracy;
5 - Adjustable velocity;
6 - Adjustable sights;
7 - Convenient, dependable, and streamlined bolt action design;
8 - Pressurized vertical CO2 reservoir;
9 - Almost effortless cocking action; and
10 - Popular pistol design for modifications
The main difference between the Mark I and Mark II is simply the caliber. For those who are unaware, the Mark I is a .22 caliber and the Mark II a .177. This obviously means a different barrel, bolt and breech seal size. The other visible difference is the colour of the grip panels. The Mark I grip is typically brown and the Mark II black. Everything else on the pistols is the same, including the valve, hammer, trigger, and metal frame.
The Crosman Mark series pistols are easy to appreciate. The grip fits the hand of most shooters and the pistol’s balance point is at the rear of the trigger guard. If the old saying “It points nice” has any application it holds true with this sweet lead thrower.
Many airgunners can’t be satisfied with only one Mark pistol. Hoarding is not uncommon among those who take the time to get to know this CO2 powered Ruger Mark 1 look-a-like. Some shooters collect the numerous variants while others take advantage of the pistol base for modifications such as the popular Custom LD Mk1 Long Range pistol.
Whether you’re a plinker or silhouette shooter, everyone seems to enjoy the Mark series trigger. The feel is wonderful for a low budget domestic pistol. A few minutes with a hex wrench will bring a rewarding 1-2 pound crisp pull. After applying some lubrication I worked at the trigger on my Mark II to see how low it would actually adjust. The minimum on this particular pistol weighed in at 1.20 pounds, using the lift method and a digital postal scale. This pull was achieved without polishing or stoning. After finding the minimum, I set the pull to a crisp 2.0 pounds which is about halfway between my HW40 and HW45 trigger weights.
Aside from the sweet trigger pull and comfortable design, there are many other reasons for desiring the Mark pistols. Rather than detailing all the reasons, I will suggest you try one out if you ever get the opportunity.
Crosman Mark II and Ruger Mark I
The manufacturing of the Crosman Mark I and Mark II single shot CO2 pistols began in 1966. The Mark I production ceased in 1983 but the Mark II continued on until 1986. The original versions of these pistols had the following features:
- Dual velocity settings;
- Velocity adjustment screw;
- Toggle style piercing cap;
- Cast alloy bolt knob;
- Steel bolt guide;
- Side screws for securing bolt guide;
- Tapered grip screws; and
- 6 digit serial numbers.
Dual Velocity Settings
The dual stage sear has been a retained feature for the full 40 years of production. Both calibers of the Mark pistol come with the two choices of power, which are selected with the cocking knob position. The difference between the two cocking positions is approximately 100 fps with medium weight pellets (7.9gr/14.3gr).
Velocity Adjustment Screw
In 1975, or thereabouts, the Mark series pistols started undergoing a series of small design changes. The loss of the velocity adjustment screw was one major change in this year. The barrel sleeve casting was modified by eliminating the drilled and tapped hole and the lug that supports the internal components of the hammer spring and guide. Due to the information from Crosman service bulletins, the date for this change can be confidently stated as July 1975 (see attached Crosman documentation).
The adjuster screw allowed fine tuning of the velocity between the extremes of the Hi and Lo power settings. Velocities below the Lo power setting were also possible with the use of the adjustment screw. Lower velocities yield higher shot counts, which may be desirable for economical indoor paper punching. When the velocity screw was omitted, the frame also changed to eliminate the raised Hi and Lo markings and the respective arrows.
July 1975 Velocity Screw Change
Piercing Cap Styles
The original toggle piercing cap was changed to the button style in mid 1975. The cap style was changed due to customers failing to flip the piercing lever to the home position prior to shooting. This neglect compromised velocity and resulted in customer complaints. See the attached service bulletin for details.
Apparently, the practice of some Crosman repair depots was to replace the earlier caps with the new style when pistols were sent in for service. This eventually resulted in many pre '75 pistols having the push button style of end cap.
April 1975 Piercing Cap Change
The cast alloy bolt knobs seem to be much more common than the machined and blued style of knob. The original painted cast knob has an intentional resemblance to the Ruger MkI cocking knob while the knurled steel knob is more functional in design. Although both designs look fine, the steel knob seems to have more appeal, at least to some of us.
There have been some speculations as to why the two versions exist. One thought is that Crosman contracted out all or part of this component production to other companies. The knurled steel bolt knobs seemed to appear well after 1975, when stock piles of the original design may have been depleted near the last runs of the Mark pistol production. Contracts for the knobs may have began around this time rather than tooling up to cast/machine the small part at the Crosman facility. Another thought is that Crosman may have encountered problems with their casting apparatus and used sub-contractors to bring inventory up to match the final frame production runs. It's all just speculation.
The Mark pistols can be found with two different bolt guides. One guide is made from machined and blued steel while the other an injection molded plastic. From examples seen, evidence points to the synthetic guide being introduced just prior to 1975. Post ‘75 guides are typically synthetic while pre ‘75 are often metal although the newer synthetic guides can also be found on pre ’75 pistols.
The first production of synthetic guides were mated to frames having the side guide screws. These guides had the threaded holes to accommodate the two screws. Sometime after the mid 70s, when the side screws were omitted, the synthetic guides still contained the threaded holes until stock piles were depleted. I have seen several guides with threaded holes that serve no purpose.
Side Screws for Securing Bolt Guide
The original Mark frames had the side screws for securing the drilled and threaded metal bolt guide. These frame holes seem to have disappeared sometime shortly after 1975. It’s difficult to indicate a specific year but the dated service bulletins and service manuals, with parts numbers, seem to point towards the mid 70s. The parts diagram in the 1975 service manual shows the side screws with parts numbers but a later service manual, with an April 1978 parts list, indicates the screws have already been omitted. This was also close to the time when the serial number changed from 6 digits to 9 digits and was moved from the right side of the rear frame to the left. These two changes may have occurred on the same frame variant.
Several different grip screws can be found on Mark pistols. From the Crosman parts diagrams we can be confident that the oldest design is the tapered head style. This older style can be found as a machine or self-tapping screw, with a slotted or Philips head. The newer grip screws are typically pan head, slotted, self-tapping screws. All factory screws appear to be blued steel. Brass, aluminum or other materials do not seem to be original Crosman production.
Crosman Mark I and Mark II pistols were made with a variety of different serial number configurations.
- 6 digit numbers;
- 5 digits and one letter;
- 9 digits; and
- 8 digits and one letter; and
- No serial number at all.
Serial numbers can usually be found on the right or left side of the frame, immediately below the rear sight. Typically, the 6 digit numbers are located on the right side of the frame and the 9 digit on the left but exceptions are sometimes seen.
Some Crosman enthusiasts feel the 9 digit serial numbers have a post ‘75 date code imbedded in the first 3 digits. My recent survey found 10 examples of 9 digit numbers with 5 possibly containing a date code. This is evidence enough to prove the theory is wrong or not consistent with all 9 digit pistols. In any case, it doesn't seem to be a reliable method to determine the date of manufacture.
One theory on serial numbers is that the frames started with 6 digit numbers but topped out around 1975, which resulted in frames with no serial number indications at all. Letter prefixes were then added until tooling could be changed to the 9 digit serial numbers. Letters may have been added to 8 digit numbers near the last years of production. This is only speculation with no firm evidence except for the presence of all the different serial number variants.
Variations are also seen in the Mark I/II barrel nuts used for securing the muzzle and breech (see reference pics below). The most common breech nut is seen in the upper left picture with the less common knurled nut directly below. Once again, this may be the result of contract work for Crosman parts or there may be some other explanation for the variants.
The next pair of pictures show the common muzzle nut, top center, with a rarely seen muzzle nut bottom center. The rare nut appears to be made of the same powdered iron as the trigger parts. The undercut at the muzzle just barely clears the barrel (thick wall). The end that contacts the inside of the shroud is the large taper, approximately the same size as the common type.
The main difference in the lower two muzzle nuts is where they meet the barrel shroud. The first type has a sizeable tapered edge while the second type has a small chamfer, with a pretty much flat bearing surface. They are both machined steel parts with a blued finish. The first type is most commonly seen on pre '75 guns, the second type on post '75 guns.
Over the many years of manufacture the colour tones in the Mk I grips have been found ranging from a dull matte brown with no colour swirls to a high gloss grip with highly visible contrasting colour swirls. The Mark II grips range from a dull black to a high gloss shine. These grip variants seem to be independent of the year of manufacture and are not a good way to speculate dates.
Exceptions to the General Rules
Although the above mentioned dates were carefully researched, there are many Mark series pistols that create exceptions to the data. Some of the common reasons for the non-compliant pistols are:
- Owner’s changing parts or swapping amongst pistols
- Part’s changed during warranty work at repair depots
- Transitional pistols with parts from previous variants
My Mark II seems to be an example of a non-compliant pistol. The presence of the velocity adjuster screw and 6 digit serial number indicates it’s a pre ’75 model. The lack of bolt guide screws indicates it’s a post ’75 pistol. My guess is that the production year was close to 1975, during the transition period when old parts and new style parts were found on the same pistol. The 984XXX serial number also indicates it’s probably a mid 70’s pistol.
As you have likely noticed, it’s very difficult to obtain an exact date of production for these pistols. It’s a lot easier to just appreciate the variants you have and observe the differences in other versions that pass through your hands.
Although I appreciate the Mark series pistols, I’m not very knowledgeable on the history and variant information. I give full credit to Leonard Joe for supplying all the details and pictures through email correspondence. He patiently played the “question & answer” and debating routine for countless emails.
Once all the information was gathered, I organized the pile and put everything into my own style of words for the review.
My role for the History section was that of the organizer and writer, not the originator of the facts. Leonard has a wealth of material, notes, and understanding of the Mark pistols and other fine airguns. We are fortunate to have him take the time to share this with us all. Many thanks Len.
Results of Mark I/II Survey
I would like to thank all those who contributed to the survey I posted on three of the popular airgun forums. Information from a total of 50 pistols was submitted for statistics. The summary follows:
70% of the examples were Mark I pistols, 30% Mark II
72% had the velocity adjustment screw
70% had side screws for bolt guide
68% had lever piercing caps, 32% had button piercers
78% had cast alloy bolt knobs, 22% had machined steel
60% had tapered grip screws, 40% had pan head screws
90% of the grip screws had slotted heads, 10% had Philips heads
6 digit numbers = 66%
5 digits + 1 letter = 2%
9 digit numbers = 20%
No serial number = 12%
Mechanism: Single shot, bolt action
Overall Length: 11”
Barrel Length: 7 13/16”
Rifling: 10 grooves, one turn in 16”
Calibres Available: Mk II -.177, Mk I = .22
Weight: 2 lbs 9.6 oz (empty)
Rear Sight: Adjustable for elevation and windage
Sight Radius: 9 3/4”
Scope Groove: None
Grips: Contoured plastic with thumbrest
Trigger: Double sear, adjustable engagement
Velocity Ratings: Adjustable - see chart below
Safety: Manual lever safety
Copied from Crosman Mark I and Mark II Owner’s Manual:
Crosman Mk I & Mk II
.177 cal Mk II – 7.9gr
Lo - 320 fps, Hi - 420 fps
.22 cal Mk I – 14.3gr
Lo - 300 fps, Hi - 400 fps
*Approximate velocities at 72 degrees Fahrenheit with Crosman Superpells.
Note: All Mk I and Mk II models have dual velocity settings. Early models also have a velocity adjustment screw for fine tuning the velocity between the Hi and Lo settings.
My tests have indicated that a typical Crosman Mark 1 will shoot a 14.3 grain pellet at 400-410 fps at 68 degrees Fahrenheit. Of the seven pistols tested, six agreed with this statement. The seventh pistol was only shooting around 365 fps because of a tired hammer spring. Velocity was eventually restored to factory level with the installation of a new spring.
Since the Mark 1 pistol was last manufactured over 20 years ago, the hammer and valve springs occasionally become weak. This can create variations from typically found velocities. A weak hammer spring in conjunction with a healthy valve spring will usually cause velocity to decrease. A healthy hammer spring along with a weak valve spring can enhance velocity output. Spring changes are actually a cheap method of adjusting velocity above 410 fps. With a stronger hammer spring I managed to get a few Mark 1 pistols shooting 440 fps with 14.3 grain pellets at 68F temperatures. Tinkering with valve duration is a simple way to increase velocity by approximately 10%. The downside is the decreased shot count per powerlet. My count dropped from approximately 45 powerful shots to 23 shots. For indoor shooting a velocity of around 365-370 fps will punch holes at 10 metres and also give in the neighbourhood of 65 accurate shots from a 12 gram supply.
The Mark II pistol also gets close to the manufacturer’s stated velocity output. Numbers in the 420-430 fps range with 7.9 grain pellets are about normal. My pistol is closer to 400 fps but shot count is also up around 80-85 per powerlet. Testing 5 powerlets gave 80, 82, 83, 83, and 85 full power shots per bulb. The POI at 10 metres dropped by around 1/2” after the 80-85 shots. Since this pistol is mainly an indoor shooter, I have no desire to tinker with the springs for more velocity and less shots per 12 gram bulb.
Benchrested Groups - Mark II
For testing the Mark II accuracy potential I removed the grip panels and clamped the frame in a Black and Decker Workmate. A distance of 10 metres was measured and target papers were mounted to a cardboard backer. There was no need for a bullseye aiming point since the POI is not important. After each group I would either move the paper slightly or replace it.
5 shot groups @10 metres
Cros Premier - 7.9gr - 4.50 - .30, .32, .29, .29, .32 - Ave = .30" ctc
JSB Match - 7.3gr - 4.49 - .22, .35, .32, .34, .31 - Ave = .31" ctc
JSB Exact - 8.4gr - 4.52 - .24, .32, .39, .23, .40 - Ave = .32" ctc
H&N Finale Match - 7.7gr - 4.50 - .37, .42, .23, .34, .45 - Ave = .36" ctc
RWS Meister - 8.3gr - 4.50 - .30, .48, .32, .36, .37 - Ave = .37" ctc
Cros Supermatch - 7.9gr - 4.50 - .38, .36, .40, .47, .39 - Ave = .40" ctc
RWS Super-H-Pt - 7.4gr - 4.50 - .43, .48, .40, .45, .38 - Ave = .43" ctc
5 shot groups @10 metres (2nd test)
H&N Finale Match - .30, .34, .32, .26 Ave = .31" ctc
JSB Exact - .28, .37, .33, .30 - Ave = .32" ctc
JSB Match - .26, .28, .43, .33 - Ave = .33" ctc
Cros Premier - .43, .36, .30, .30 - Ave = .35" ctc
10 shot groups @10 metres
JSB Exact - .45, .45, .37 - Ave = .42" ctc
JSB Match - .46, .34, .45 - Ave = .42" ctc
H&N Finale Match - .47, .38, .46 - Ave = .44" ctc
From a distance of 10 metres, this particular Crosman Mark II seems to average around .30" ctc for 5 shots and .45" ctc for 10 shots. The pistol does not seem to be pellet sensitive, shooting quite accurately with 4 different pellets that were tested.
I consider the accuracy results to be quite reasonable considering the intended market and original retail price for the pistol.
The .177 calibre pellet availability was not exhausted and other types of pellets may give better/worse results.
5 Shot Groups
10 shot Groups
Power Parts – Seals & Springs
On many occasions I was faced with a leaking Mark pistol and no extra seals to fall back on. A short trip to the hardware store provided a couple of workable sizes for three different applications on the Mk. I realize these are just cheap 25 cent black plumbing o-rings, likely 70D nitrile, but they seem to hold okay. The bolt seal doesn’t take constant pressure so the softer seal doesn’t appear to be effected. The piercing pin seal and valve body seal are “trapped” and have nowhere to expand. They will likely tear up and leak in the future but so far they hold gas for more than a week. When they eventually die I will replace them with the proper material and not have to think about them again for many years.
I’m not promoting the use of substandard seals but these standard o-ring sizes are what I found to fit and function in the Mark pistols, at least temporarily.
- Bolt seal (Mk1) = ¼”OD x 1/8”ID x 1/16” thick
- Valve body seal = 5/8”OD x ½”ID x 1/16” thick
- Piercing pin seal = ¼”OD x 1/8”ID x 1/16” thick
A quick email to Tim at Mac-1 resulted in the correct o-ring sizes for the Mark pistol seals. Tim recommends mil spec 90 durometer urethane seals for all applications, although a softer seal will work on the bolt.
- Bolt seal (Mk1) = 006 softer seal (005 with hard seal)
- Bolt seal (Mk2) = 004 softer seal (003 with hard seal)
- Valve body seal = 014
- Piercing pin seal = 005
- Piercing body seal = 113
Sometimes it’s just not worth driving around looking for seals or spending a half hour on the phone to find a cheap product. Tim sells the proper seals for $2 each, plus $1 shipping. Add a few seals for no extra shipping http://www.mac1airgun.com/ ).
The valve stem seal on the Mark pistols is not a removable o-ring seal. When this seal needs replacing it’s usually best to send the stem to someone with the equipment to do the work. It is not something the average airgunner would tackle.
Basic Mark Pistol Disassembly
1 – Remove grip screws, grip panels, and piercing assembly.
2 – Loosen rear sight windage adjustment screws (140-9).
3 – Remove rear sight screw (10-18) while holding pistol upright.
4 – Hold pistol upright and remove rear sight blade (10-17).
5 – Old Marks have a set screw under sight blade that is removed next (10-14).
6 – Carefully remove detent spring (10-15) and detent ball from hole (10-13).
7 – Remove elevation screw (10-19) and elevation washer (10-40).
8 – Old Marks have bolt guide screws that are removed next (10-64).
9 – Carefully pull bolt guide assembly (10-61) out back of frame.
10 - Remove barrel nut (10-4) at muzzle. Use spanner or needle-nose pliers.
11 – Slide barrel housing (10-2) out of frame.
12 – Loosen barrel set screw (10-6) located on top of front section of receiver.
13 – Remove barrel nut at breech (10-5).
14 – Slide barrel out of frame.
15 – Slide hammer spring (10-23) out of hammer (10-22).
16 – Remove cocking knob end (10-59) and shank (10-21) from frame.
17 – Slide hammer (10-22) and hammer sleeve (10-24) out of frame.
18 – Remove trigger guard screw (10-66) and trigger guard pin (10-44).
19 – Remove trigger guard (10-12).
20 – Remove trigger spring (10-34).
21 – Drift out trigger pin (10-32).
22 – Remove trigger (10-33) and sear (10-33).
23 – Remove valve screws (10-26) from side of frame.
24 – Pry valve (10-25) from frame using large slotted screwdriver in valve slot.
25 – Valve will pop out with stem (10-67) and valve spring (13-29).
- To create leverage for valve removal, I use an old screwdriver handle or wood dowel as a fulcrum.
- Valve body seal (600-28) often sticks to frame and valve.
- If seal sticks to valve body, it is sometimes necessary to carefully polish off stuck pieces using 0000
- There is usually no need to remove the safety assembly.
Button Piercer Disassembly
1 – Use small slotted screwdriver or dental pick to carefully pry star washer out of cap.
2 – Slide thick washer out of piercing cap.
3 – Inner o-ring seal can be seen at base of piercing pin.
4 - Carefully remove inner seal with probe, xacto knife or dental pick.
5 – Replace piercing pin seal (600-84) with new o-ring seal.
6 – Replace piercing body seal if necessary (150-54).
- Piercing pin seal (600-84) will usually be damaged during removal so do not remove unless leaking.
- It is not necessary to completely disassemble all piercing assembly parts for seal replacement.
Use spanner or needle-nose pliers
Mark I disassembled
The Crosman Mark I and Mark II pistols are not difficult to shoot accurately. The CO2 power source makes them virtually recoilless and the 2.5+ pound weight helps tame the muzzle flip. The Mk series pistols are over ¾ of a pound heavier than the unaltered Crosman 2240 model. My own Mk II example has no noticeable recoil or muzzle jump when shot at the current power setting.
As with all short barreled CO2 pistols, the muzzle bark gets a bit sharp when valve duration is increased. When set to 440 fps (14.3 gr) my Mark 1 had noticeably more bark and muzzle jump but this is the nature of an unmoderated gas pistol. At factory velocities I find the Mark pistols are very tolerable for indoor/outdoor plinking. If the noise level becomes bothersome for indoor shooting, the velocity can be dropped by utilizing the low power sear setting. With that being said, these are not the pistols for low noise requirements. A single stroke pneumatic or springer would be more inline with filling a need for a quiet shooting pistol.
The unaltered Mark is comfortable for single hand and two handed shooting. The neutral balance and contoured thumbrest allow a shooter to relax with a one hand hold. The pistol seems to “hang” in position without any tendency to dive at the muzzle. Two hand shooting is equally comfortable due to the absence of cocking levers and slab side grips.
Custom Work & Photo Gallery
Mark 1 pistols - 6" barrel, factory barrel length, and 12" barrel
Using 14.3 grain pellets, this 12” barrel does about 495 fps with a hangy tank and 485-490 fps on powerlets. (courtesy of Leonardj)
Three Mark 1 pistols in pieces (courtesy of Leonardj)
Top row, L to R: early Mk I, later Mk I with flip-top box, early Mk II.
Bottom row, L to R: 6" bbl Mk1; stock Mk1; 12" bbl Mk1; 10.5" bbl .30 cal; stock Mk1 finished in Birchwood Casey Aluma-Black. The .30 cal. Mk I is presently shooting at 348 to 363 fps with lead balls and hangy tank. (courtesy of Leonardj)
Mark I/II package changes (courtesy of Leonardj)
Mark 1 with 12” Mac-1 LD barrel and custom bolt knob (courtesy of ETA)
This pistol shoots 495 fps with JSB Exacts. No heavy valve mods done.
Custom Mark 1 (courtesy of Ken Jackman)
The Custom LD MKI Long Range CO2 Pistol
I’m not one for promoting individual dealers on my web site but the LD MKI pistol only comes from one dealer. It’s definitely a worthwhile addition and I felt the review would be lacking without it.
The LD MKI design is a result of the joint customizing efforts of Larry Durham and Tim McMurray. Larry designed the barrel, hangy tank adapter and recontoured bolt probe. Larry's designs in combination with Tim's valve mods, trigger work, and tuning tweaks formed the popular Custom LD MKI Pistol. The pistol was originally designed for silhouette competition but it also excels at hunting and long range plinking.
The LD pistol is a basic Crosman Mark I with the following custom features:
- Custom fitted Weihrauch barrel (10”, 12”, and 14” available);
- Choice of bull-barrel or 3 baffle brake;
- High power custom valve with dual body seals and 3 angle seat;
- Balanced valve for decent velocity consistency from 45 to 95 degrees;
- Trigger tune;
- Scope grooves cut into frame with 30 minute angle adjustment;
- Re-contoured bolt probe to facilitate airflow;
- Bulk adapter and 3.5oz hangy tank system;
- Bead blasted frame with flat black baked on paint finish; and
- Optional Millet rear sight and improved front sight.
During the email exchange, Tim took the time to answer all my questions and provided several pictures for the review. As always, I had to know about accuracy and velocity.
Custom LD MKI Details
Accuracy: 1 hole at 10 yards, 2 holes wide at 20 yards, and 1 inch at 50 yards.
Velocity: 400fps on low, 560 fps on high, and 600 fps possible with light pellets.
Distribution: Over 750 LD pistols sold since 1984.
Contact Mac-1 for further details on the LD pistol.
Custom LD MKI Pistol (courtesy of Mac-1)
Custom LD MKI Pistol with 10” barrel (courtesy of DaveR)
LD MKI Millet rear sight option (courtesy of Mac-1)
LD MKI barrel option (courtesy of Mac-1)
Custom RB Grips for Crosman Mark series pistols
Steve Corcoran Shoulder Stock (courtesy of Mac-1)
Originally posted Leonardj.