by Tom Gaylord
Writing as B.B. Pelletier
The MAR177 from Crosman.
This report covers:
- Baseline with Hobbys
- Today’s test
- What is the average?
- Second page of numbers
- What does “estimate 601” on page 2 mean?
- But — what is the average velocity?
- Pressure gauge and fill pressure
- Big lesson
- Balanced valve
- How do I know the ending air pressure?
- Air Arms Falcons
- RWS R10 Match Pistol
- H&N Finale Match Light
- Loading problems
Today I test the velocity of the MAR177 I’m reviewing, and I have a baseline from the 2012 test I did, with which to compare it. Some of you asked me what velocity to expect. Well, it is all in the 6-part review I did on the first MAR177. Look at Part 3 of that series for the velocity test.
Baseline with Hobbys
In that 2012 test I got an average of 609 f.p.s. from RWS Hobbys and the velocity varied by 32 f.p.s. The low was 593 f.p.s. and the high was 625 f.p.s. I got a shot count of 124 shots on one fill.
Today I shot 160 Hobbys on a fill. The fill pressure ranged from a high of 3200 psi to a low of about 2200 psi — according to my accurate carbon fiber tank gauge. Those starting and ending pressures are well above the pressure range of the first gun (which was 2900 psi to 1600 psi).
In those 160 shots my highest velocity was shot number 106 that registered 604 f.p.s. My lowest velocity was shots number 156 that registered 571 f.p.s. That is a spread of 33 f.p.s. for 160 shots. However, I thought the rifle fell off the power curve on shot number 145, where the velocity was 578 f.p.s. If I take the first 140 shots, the low was 580 f.p.s and the high was 604 f.p.s. That is a spread of 24 f.p.s. I can live with that.
What is the average?
I didn’t tell you the average velocity for Hobby pellets, did I? The reason I didn’t is because of the huge amount of data I collected. Let me show you.
These are the velocities of the first 50 shots.
There is no way I am entering that data into WordPress, because when I edit, the software makes me highlight EACH NUMBER, click backspace/delete and then hold down the Shift key and click Return! For EACH NUMBER!!!
If you are reading this on a smartphone you had best learn how to scroll because I am going to refer to those numbers A LOT!
Second page of numbers
Let’s look at shots number 91 and 92 at the top right of the second page. Why is the velocity 492 f.p.s.? Because I double-loaded a pellet by mistake! So — yes, it is possible to load more than 1 pellet, and I disregarded that velocity for this test. The average for that column is the lower 8 shots.
What does “estimate 601” on page 2 mean?
By the time I had fired 70 shots I saw the velocity start to rise and, at the time, I thought this rifle was going to average in the 600s with Hobbys. So I wrote my estimate of what the third column velocity average would be before shooting the string and then I took a picture of that page — so you could see that I was just guessing. And I missed the average velocity by 5 f.p.s.
I estimated what the next string’s average velocity would be.
But — what is the average velocity?
I’m not going to enter all those numbers again and find the average. But, if I take the averages for each string of shots from number 1 to 140 and combine them to find the average for all of those averages, that number is 594 f.p.s. I’m calling that the average velocity at which this MAR177 shoots 140 RWS Hobby pellets — with a low of 580 to a high of 604 f.p.s. It’s very close to the true average, if not right on. At that average velocity Hobbys developed 5.49 foot-pounds of energy.
The first MAR I tested in 2012 averaged 609 f.p.s. with Hobbys over 124 shots on one fill and this one averages 594 f.p.s. over 140 shots on a fill. The first MAR177 varied velocity of Hobbys by 32 f.p.s. over its range, this one varies 24 f.p.s. over its range. The first gun was faster and this one gets more shots per fill and is more consistent. But the tests of both guns give you a good idea of how the MAR177 performs.
Normally there aren’t any photos on velocity day. This time I took 22 photos — 18 of the pressure gauge before and after every ten shots. I will now show you a few of those but I won’t overload you.
Pressure gauge and fill pressure
I’ve already said that the valve in this MAR177 uses higher pressure than the first one I tested. It also uses higher pressure than the manual recommends. The manual says that 2900 psi is the maximum fill pressure. I filled to 3200 psi this time to get both the top and bottom of the power curve. That was the pressure I saw on my carbon fiber tank gauge when the fill was complete. Look at what the onboard gauge said.
The onboard gauge read this when my accurate tank gauge said 3,200 psi. The needle is close to 3400 psi.
After the first 10 shots the gauge read this.
After 50 shots the gauge read like this.
After 100 shots the gauge read like this.
After 140 shots the gauge read like this. I am calling this the end of the power curve. This is as low as I will let the onboard gauge get when shooting the MAR.
After 160 shots on one fill, this is what the onboard gauge read.
This gauge illustrates a really big lesson. Do not go by what the small onboard gauge on your PCP says, unless you have tested it and know it’s right. When I worked at AirForce I took all the complaint calls and after the Condor came out many of them were complaining that the Condor wasn’t giving them all the performance they paid for. How did they know? They pressurized their rifle to 3,000 psi on their tank’s gauge (AirForce rifles did not have gauges on them in those days) and the velocity was way too low. I told them to keep shooting the rifle until the velocity increased to over 1,200 f.p.s. with .22-caliber Crosman Premiers and then I told them how to determine how much pressure their rifle needed to get that speed. Some were happy with that, but others insisted that they weren’t getting what they paid for if the gun did not perform at 3,000 psi. I had no good answer for them.
Their rifles got 20 good shots with .22-caliber Premiers at over 1,200 f.p.s. and yet they thought they were getting shortchanged because the gun wasn’t doing it at 3,000 psi on their gauge. Did they think they would get MORE shots at that velocity with the higher pressure? No, they wouldn’t. Some even knew that because they had tested the rifle before calling in.
What they were saying, in effect, was their new C8 Corvette may be capable of going 194 m.p.h., according to a calibrated radar gun, but when they do, the speedometer in the car only reads 177 m.p.h. Well — which do you want, a 194 m.p.h. car with a speedo that’s not quite right and sells for under $60,000, or a 194 m.p.h. car whose precision speedometer also reads 194 m.p.h. , making the car retail for $74,000? Some guys can adapt and others can’t.
There — I got that off my chest. Until someone else says the same thing.
What you are seeing with the MAR177 is the result of a balanced valve. Did Crosman set it up just for me? Not unless they have a Wayback machine or a crystal ball! I bought this New Old Stock air rifle off Ebay five years after Crosman stopped making them. This is what can be done with a PCP when:
1. The engineer knows what he is doing, and
2. The velocity is kept low.
How do I know the ending air pressure?
Okay, smart guys. Wanna tell BB how he knows that the ending air pressure (after 140 shots) is really 2,200 psi and not what it says on the gun’s gauge (just under 2100 psi)? This is a test and you will be graded. Do not look on anyone else’s paper.
Air Arms Falcons
I tested Air Arms Falcon pellets next. This time I pressurized the rifle to 2900 psi (using my carbon fiber tank gauge) and only shot a string of 10 for each pellet that follows. I’ll start with the Falcon.
Ten Falcon pellets averaged 611 f.p.s. The low was 590 and the high was 617, so a difference of 27 f.p.s. At the average velocity Falcons developed 6.08 foot-pounds of energy.
RWS R10 Match Pistol
Next to be tested were 10 RWS R10 Match Pistol pellets. They averaged 619 f.p.s. with a spread from 609 to 627 f.p.s. That’s a difference of 18 f.p.s. At the average velocity the R10 Match Pistol pellet develops 5.96 foot-pounds at the muzzle.
H&N Finale Match Light
The last pellet I tested was the H&N Finale Match Light. It was also the heaviest pellet. They averaged 592 f.p.s. with a spread that went from 586 to 598 f.p.s. — a difference of 12 f.p.s. At the average velocity this 7.87-grain pellet developed 6.13 foot-pounds at the muzzle.
While I was testing the last three pellets I encountered a problem with loading some of the pellets. Even the Falcon domes did it. If I held the rifle with the muzzle pointed up, sometimes the pellets would jam as I tried to close the bolt. I played with this for a while before discovering that if the rifle is held level it never happens. Just hold the rifle like you are shooting at a target and it feeds fine!
Sorry to tell you this guys but this MAR177 rates a 1.8 on the Pyramyd Air loudness scale. It is one of the quietest air rifles I have ever tested. A Red Ryder is quieter, but not by much!
So far this old gem is performing well. It’s even better than I remember — thanks mostly to my Geissele trigger, but also to the efficient use of air.
The first accuracy test comes next. I can’t wait!