by Tom Gaylord
Writing as B.B. Pelletier

Crosman MAR
The MAR177 from Crosman.

Part 1
Part 2
Part 3
Part 4
Part 5

History of airguns

This report covers:

  • Sight-in
  • First group
  • Qiang Yuan Olympic pellets
  • RWS Hobby
  • JSB Exact RS
  • Discussion
  • Summary

You asked me to back up to 25 yards with the Crosman MAR177 and today is the day I do it. It should prove to be an interesting report.


Because I was using the iron sights that came with the rifle, I skipped the sight-in at 12 feet and went straight to 25 yards. My sight-in pellet was the Air Arms Falcon that was so accurate in the test at 10 meters.

The first shot went two inches high at 25 yards. After seeing that I adjusted the rear sight down 5 clicks. I had adjusted it up the other day for photography when I was exploring its adjustability and writing Part 5.

Dropping 5 clicks dropped the second pellet 8 tenths of an inch, so I was still above the bullseye. I then adjusted the rear sight as low as it would go, which was only another 6 clicks. Then I just shot the remaining 8 pellets without looking through the spotting scope again.

I’m not going to measure this “group” because of the sight adjustments that were made. But I will let you see it.

MAR sight in
The sight-in target was shot from 25 yards with Falcon pellets. The 8 shots in the black were fired with the same sight setting.

Obviously this pellet is hitting too high, and the rear sight is as low as it will go. The only solution is to adjust the front sight higher. I used my new 1/8-inch roll pin punch to adjust the front post up 5 clicks. Remember, adjust the front sight in the direction opposite of how you want the pellet to move.

First group

I shot ten more Falcons after adjusting the front sight up. Ten pellets went into a group that measures 0.793-inches between centers. I pulled the second shot because I was trying to take up the stage one trigger pull and I fired the rifle before I was settled in for the shot. So I am blaming the trigger for that shot. However, even with that I got a decent group at 25 yards with iron sights. But the group is at the bottom of the bull. Apparently the front post adjustment moves the strike of the rounds farther than the rear sight adjustment.

Falcon group
The group of Falcons after adjusting the front post is 10 shots in 0.793-inches at 25 yards. Adjusting the front post up 5 clicks dropped the group to the bottom of the bull.

Qiang Yuan Olympic pellets

Next to be tested were the Qiang Yuan Olympic pellets. These weigh almost a full grain more than the Falcons, so I did not change the sight setting. I did not look at the target while shooting this group and it wasn’t until I walked down to the bullet trap to change the target that I saw what had happened. Ten pellets landed in a round group that measures 0.411-inches between centers. It’s the best group of the test, and I was astonished that the MAR could shoot this well. Five shots landing this tight might be called luck, but ten is something more. Ten shots this tight tell us that with the right pellet the MAR can shoot!

Chinese Olympic group
The MAR177 put ten Qiang Yuan Olympic pellets into 0.411-inches at 25 yards. This is the best group of the test.

After seeing how low on the bull the Chinese pellets hit I adjusted the rear sight up one more click up — making the total rear sight adjustment 6 clicks up.

RWS Hobby

The next pellet I tested was the RWS Hobby that did well at 10 meters. At 25 yards the MAR put 10 of them into a 1.098-inch group. Obviously Hobbys fell off at this distance, as we expect all wadcutters to. Can’t figure out the Qiang Yuan Olympic pellets though!

Hobby group
Then Hobby pellets went into 1.098-inches at 25 yards.

Obviously one click up did not move the shots high enough so I adjusted the rear sight another 2 clicks up. That’s a total of 8 clicks up after I adjusted the front post 5 clicks up.

Shop Benjamin Rifles

JSB Exact RS

The last pellet I tested was the JSB Exact RS. This dome is similar to the Falcon pellet so I thought it might be a good one for the MAR. This time the rifle put 10 pellets into 0.923-inches at 25 yards. This group was a little higher in the bull but it was also a trifle off to the left.

RS group
The MAR shot 10 JSB Exact RS pellets into 0.923-inch group at 25 yards.


The MAR177 shot better at 25 yards than I expected — at least for one pellet. The sights allow for precise shot placement because there are elevation adjustments front and rear.

I think I will call this test finished and move on to mount a scope on the MAR. That should give us a good look at the potential accuracy.

I still don’t care for the trigger. I think it was the reason for my thrown shot on the first group and I have to get accustomed to it every time I shoot the rifle.


The Crosman MAR177 is performing as it was designed to. It’s a top-flight pellet gun upper for the AR-15. It fits any AR-15 receiver that has standard-sized 0.154-inch pins, as opposed to the larger 0.171-inch Colt-style assembly pins.

It is unregulated, and handles air sparingly, getting up to 160 shots on a fill with 145 of them differing in velocity by just 24 f.p.s. The 10-shot rotary magazine works well, as long as the rifle is level when cocked. If the muzzle is elevated there can be a jam or a failure to feed.

Crosman built the MAR with the best of materials. They made it to shine, and shine it does. I am excited to shoot it with a scope, but I believe I’ll give you a break before I do.