How consistent is a multi-pump?

by B.B. Pelletier

Today, we’re going to look at shot-to-shot consistency in an airgun many consider inexpensive – the Sheridan Blue Streak. And, of course, anything I say about the Blue Streak holds true for the Silver Streak, as well. This is an experiment I read about years ago, and it’s a real eye-opener. It also gives you something to do with that new chronograph you get for Christmas.

Consistency is king!
In the world of airguns, the watchword is consistency, as in how close each shot’s velocity is to all the others in a given string. I have known shooters, and perhaps you have too, who get so wrapped up in the quest for the lowest possible shot-to-shot variation that they don’t shoot at targets anymore. They just shoot shot after shot through the chronograph, searching for a gun/pellet combination that never varies.

Consistent velocity is an important indicator of the state of an airgun’s tune, but it’s no guarantee of accuracy. Some very accurate pellets will vary a lot in velocity, while some consistent pellets are mediocre downrange. Still, a number is very compelling.

So, how consistent is a relatively inexpensive air rifle like the Sheridan? Whadda ya think? Ten shots within a 30 f.p.s. spread? 20? 10? Well, before we go try it, there’s another aspect to this. Because the Sheridan is a multi-pump, it can shoot on any number of pump strokes between three and eight. So, will the consistency vary with the number of strokes?

And, there’s something else. Some guys say that how fast or slow you pump the gun makes a difference in the consistency. So, we have to explore that, too! Didn’t I tell you this was going to be fun?

Shot-to-shot consistency with different numbers of strokes
There is no difference in consistency at three pumps all the way up to eight pumps. Shooting Crosman Premiers, my Blue Streak never varied by more than 10 f.p.s. from the fastest shot to the slowest in a string of 10, regardless of how many pump strokes were used. There was a best string on five pumps that varied just five f.p.s.; but the other strings were so tight that, if I tried enough times, I would get the same results on all the numbers of pump strokes.


Even this old Silver Steak from the 1950s is extremely consistent, shot to shot.

I tried this test again with an old Silver Streak I have. Though that gun varied by as much as 12 f.p.s. in one of the strings, it also exhibited the same consistency regardless of the number of pump strokes

Fast pumping vs. slow
This was another walk in the park! The Blue Streak averaged 1 f.p.s. faster when pumped as rapidly as possible, as opposed to taking five seconds to complete each pump stroke. I didn’t test this at every number of strokes – but at 3, 5 and 8, it stayed the same.

Are you surprised?
It’s been my experience that multi-pump pneumatics are among the most consistent airguns, as far as velocity is concerned. Single-strokes are just as consistent; of course, they’re pneumatics, too. Only one spring airgun I know of can equal this performance every time, and that’s the Daisy 499 BB gun – the world’s most accurate BB gun. But as a class of guns, I have to give my vote to the multi-pumps for consistent velocity.

Try this experiment with your own multi-pumps and tell us what you learn.

37 thoughts on “How consistent is a multi-pump?

  1. Ya gotta love those Sheridans. Powerful and accurate enough. Last forever and, you don’t need a truck load of support equipment. In my opinion, that makes them the cheapest and best buy on the market.


  2. I’ve been reading American Air Guns by James House. If I remember correctly, he was getting similar results with multi-pump pneumatics that were priced less than a streak. It’s a fun book if anybody’s interested.

    Matt



  3. Thanks for continuing to keep us all reading with your very interesting blogs. I was wondering if sometime you could tell us a little about the DRULOV RADA 9mm RIFLE? A 9mm slug thrower that can run on 12g carts. Sounds kinda cool.




  4. Man I’m sorry to have to tell you this but, you wasted your time. Single stroke pnuematics with fixed barrels , and side lever cocking mechanism’s like my Xisico B-21. are just as consistent and accurate from shot to shot, probably more. Do your test again but, this time with break-barrel, and fixed barrel single stroke air rifles.



  5. Hi, I’m 65 yrs old, just bought my first pellet gun since 1956 on line. (Benjamin Pump). I bought a Sheridan C9 chrome Pump. Not knowing much about what to buy, I bought it because of what I had. It seems it was the CADILLAC of air guns in 1956 and I had no problems. I find all of the comments very interesting. My puzzlement comes as to what type of 20 cal pellet to buy. It appears there is about 8 to 12 to choose from. Any comments, help or suggestions would be appreciated. Mostly I bought this for my grandson who is 12. I am also contemplating buying a air pistol…..this is really confusing to select a type….Input would be appreciated.
    thanks
    Big voodoo (wroberts@datastar.net)


  6. Big voodoo,

    Howdy! I’m 58, so we’re from the same era.

    You made a great buy when you bought that Sheridan! Your new Benjamin is also a real nice gun. You have excellent taste.

    The best pellet today is either a .20 caliber Crosman Premier that Pyramyd Air no longer seems to carry or a Beeman Kodiak, which is lighter. I would try the Premiers first, and buy them in the cardboard box, where they are lot-sorted – not the metal tins, where they are not sorted by lot.

    Good luck,

    B.B.


  7. Hi B.B……….
    Thanks for your info and I’m glad to see that good american quality still lives on in some places….
    I’ll try the pellets you suggest. Pyramyd seems to stock the Beeman Kodiak 20 cal.
    Just curious, at what distance do you think the pellet will start to drop off its straight line?


  8. Hi B.B. ………………

    Are you saying that a different lot number in the cardboard boxes will have a different accuracy. makes sense….



  9. Lot numbers,

    Yes, airgunners put GREAT stock in certain lot numbers of Premier pellets.

    What you want is consistency, and the belief is that if the pellet all come from the same lot, they will be more consistent.

    Actually I misspoke myself – it’s really the die number, not the lot number, that airgunners look for. Certain die numbers are believed to produce the best pellets. But when you buy Premiers in cardboard boxes, they all come from the same die, marked on the bottom of the box.

    B.B.


  10. Two comments on the Blue Streak: I love it, and find it to be the best multi-pump I have. A couple of weekends ago I had the pleasure of knocking off soda cans at fifty yards with it. Neat! Later that evening, though, we noticed(as the Temperature here in North Texas droped into the 40′s) that the pellets in the Blue Streak were just slipping out the end of the barrel when they were loaded and the rifle was pointing at the ground. This did not happen after we brought the rifle in for a while and then reloaded it. I figure a rubber ‘O’ ring might have shrunk in the cold. Any thoughts on why this happened? Thanks.


  11. Yes, I have a very definite thought. You have some .177 pellets mixed in with your .20s, OR you had a few Peewees.

    No amount of cold weather can shrink metal enough to allow a .20 caliber pellet to slip through a .20 caliber bore. But I sure have mis-loaded pellets more than once!

    Check your ammo,

    B.B.


  12. bb
    these pellets had the characteristic shape of the Benjamin/Sheridan pellets, which is different from the .177, .22, and .25 calier pellets we were using that same evening. I really like your blog.
    Merry Christmas!


  13. BB,I need help.I found a Sheridan Blue streak just like the one on the picture(silvre streak) on my granpas closet.I want to know how old it is.I know its old cause my dad used it when he was 13 and hes 47 now and his father gave it to him with a couple of years of use.The serial number is 188138.Can you look up some info for me.I think is an original because the new one has some diferences and the one on the picture is like mine.
    Thanks BB.
    Hernan


  14. Hernan,

    Sheridan began putting serial numbers on their guns in 1972. Yours was made in 1977, which makes it a rocker safety gun and very desireable as a shooter.

    The gun in the picture was made between 1951 and 1960. It’s a thumb-safety model. You can read about it in the June 2 posting.

    Congratulations on your find.

    B.B.


  15. BB its Hernan.I thank you.But mine is a thumb safety model.In the top behind the rail if you push down to the left its an “F” as in fire and on the right is an “S” as in safe.So now im confused.Anwer me BB with what you think cause it is thumb safety model.Also oin the place where the saftys in its like the one on the pic leaned back not square.Please tell me what could this be then cause I kneew it was athumb model but not the years and my dad and my grandpa used it before 1977.So please BB can you check and tell me were can I look up this info.Still I want to know what you think because what you say really counts to me.
    Thanks
    Hernan


  16. BB im sorry for questioning you.I saw the pics and I can see what thumb safety is now.I realy thought mine was cause you have to use your thumb.Still can you tell me were to get this info so I can print it or could you get me the link.Thanks and happy christmas.
    Hernan


  17. Hernan,

    Okay, now you know the difference between a thumb safety, which is on the old Silver Streak I directed you to and a rocker safety, which is the name for what you have.

    I got the date information from Ron Elbe’s book, “Know your Sheridan Rifles and Pistols.” I don’t know whether it is still available new, but you should be able to buy a used copy from Amazon or one of the used book sites.

    The best book for you right now is the Blue Book of Airguns, 5th Edition. Pyramyd Air is selling them on this website. This book is loaded with information about airguns, and will answer many of your questions.

    I will post a blog next week about the rocker safety Sheridan that you have.

    B.B.


  18. Thanks BB.Its me Hernan.I am the CF-X guy as you call me in dicembers 29s post and told me to get a nickname to make it easier to communicate and I didnt know how but now I understand that is like DSW (thats a nickname for a guy that talks to us in dic 29s posts and others}so BB give me a nickname and ill use it and since you gave it to me you will always know who is talking.Remember im Hernan And you call me on this post Hernan but also you call me CF-X guy so lets do what you sayd.
    Thanks
    Hernan




  19. I have owned m Blue Streak for over 20 years – and I bought it used!!! I love the ability to vary the power level since I shoot indorrs in my attic at three pumps and hunt small game with 6. I have found that I get just about 80 fps extra in those last two pumps, plus I get through and through penetration at the ranges I hunt squirrels, bunnies and starlings (30 yds max, headshots only). I am good with the open sights, but to accomodate my aging eyes, I mounted a Tasco 3-9X scope in a pair of intermounts. Loading pellets is now a pain, but I can focus a lot better on making a good shot instead of trying to focus my eyes! I shoot the Sheridan cylindricals and the Beeman Crow Magnum. Both shoot very well out of my gun and perform well on game.


  20. deputy154,

    Wow, what a testimonial! If I didn’t already own a Blue Streak, I’d have to get one after reading that!

    That’s the kind of feedback the new readers need to read.

    Thanks,

    B.B.


  21. I wrote to Benjamin/Sheridan suggesting a polished brass version of the gun. They could call it a “yellow streak”. They haven’t gotten back to me yet.


  22. Benjamin made a gun like that in the 1980s. It was to commemorate America’s 6,000 + counties. They lost their shirts on it and more than half the guns went unsold for a decade.

    B.B.



  23. The one thing you didn’t mention that I could swear does happen is this…It always seemed to me that if I put 8 pumps in and shot it within a minute that it had much more velocity than if I put 8 pumps and walked the almond orchards for an hour before discharging.



  24. 8 pmps,

    Your gun may have leaked. I have tested the effects of shooting immediately and later and there is no appreciable difference. I guess the air doesn’t get that hot.

    B.B.



  25. Anonymous,

    I'm not really sure, but you might find an answer on the Crosman site.

    Also you posted to a blog written in 2007. There arn't many of us checking the old blogs.

    There is a daily blog written by B.B. and you'll reach an audience of maybe 20,000 readers. Surely some one there knows the answer to your question. http://www.pyramydair.com/blog

    See you there!

    Mr B.


  26. Sheridan,

    Unfortunately, I don't know that much about dating the streaks. Very few people monitor these older posts, so you might not get very many replies. If you posted this question to the current days' post, there is a good chance that someone there will be able to tell you exactly when it was made, or at least point you in the proper direction.



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