What happens during a spring gun break-in?
by B.B. Pelletier
Before I begin, here's a tip I just received. Pyramyd Air is now a direct importer of ALL Air Arms airguns! In the past they had to buy their guns through another importer who couldn't supply guns as fast as they needed them, so Pyramyd's owner, Josh Ungier, went straight to Bill Saunders, the head man at Air Arms, and got Pyramyd on as a primary importer.
What this means to buyers is the wait times will be greatly reduced. They will stock every American model Air Arms makes, but if you need something they don't have in stock at the time you place the order, Josh simply tells Bill to add it to his next shipment. They talk on the phone about every other day. They have already expedited several key shipments of parts and guns this way, and they look forward to a long relationship of supplying the finest British airguns to American shooters.
Today's question comes from Scott298, who wonders what happens during the break-in of a spring piston air rifle. I was going to answer him directly in the comments section, but when I ran the answer through my head, it turned out to be bigger than you might think, so I made it this whole posting.
When I got back into airguns in the mid 1970s, both Beeman and Air Rifle Headquarters were telling customers that the spring guns they sold needed a long break-in period before they would perform up to standard. Back in those days many airguns still had leather seals, plus some of the guns, such as those made by BSF, were being overbuilt. They had to be worked in just like a good baseball glove. I don't have room for all the history here, but it is fascinating - if not applicable to the guns you buy today.
The Beeman R1
In 1994, Tom Gaylord and his wife started writing The Airgun Letter, a monthly newsletter about airguns. Tom needed a project that would last a long time to fill the pages of his new endeavor, so he bought a brand new Beeman R1 and proceeded to break it in for his readers. He promised to shoot 1,000 shots and to report at intervals how things were going. That multi-part series was called the R1 Homebrew. Well, the response to what he did was very encouraging, so Tom turned it into a book, which he called the Beeman R1 Supermagnum Air Rifle, which was Beeman's name for the gun.
The R1 book by Gaylord has test results from two brand-new R1s. The book is out of print and only available used.
From that book comes the information I will now give you. His brand-new .22 caliber R1 cocked with 54 pounds of effort on the first shot. RWS Hobby pellets averaged 826.8 f.p.s. in the beginning. By shot number 200 the cocking force had dropped to 45 lbs. By shot 500 Hobbys were averaging 828.2 f.p.s. and the cocking effort was holding at 45 lbs. At shot 1,000, the rifle averaged 819 f.p.s with Hobbys and the cocking force measured 44 lbs.
Tom then removed the stock and discovered that a steel tab on the spring tube that accepts one of the forearm screws had broken at the weld. He knew that Beeman would re-weld it for him which wasn't normally a problem, except that he had planned several non-invasive tunes for the gun before actually disassembling it the first time. To weld the tab back in place, Beeman would first have to disassemble the gun and degrease the inside of the tube, which meant that the gun would then have to be re-lubricated before reassembling it. They told Tom they would have to use moly for this because they didn't have Weihrauch factory grease. That would have thrown all his test results out the window because it would have bypassed several things he wanted to do before getting to that point, so he requested a brand new rifle. To Beeman's great credit, and thanks to Don Walker, their repair manager at the time, they sent him a brand new rifle.
So Tom had to break in a second new .22 caliber R1! Cocking effort measured 55 lbs. on the first shot. RWS Hobbys averaged 862.8 f.p.s. At shot 500 the Hobbys averaged 827 f.p.s . and cocking was down to 49 lbs. At shot 1,000, Hobbys were going 837.8 f.p.s. and the cocking force measured 46 lbs. Tom went on to test the Hobbys after oiling the mainspring and they averaged 847.8 f.p.s. at shots 1036-1040.
Tom was oiling the piston seal with chamber lube during the break-in. He reported that his gun honked like a goose when cocked. Today I would not advise oiling as much as Tom did. Let the seal squeak; it will get quiet on its own. But in the mid-1990s, oiling that much was common because the Beeman instructions told you to do so.
NOW, SCOTT298 - here is the important thing. A TX200 Mk III will not perform the same as an R1. It will be much smoother on the first shot and the cocking effort will not change as much as it breaks in. But after perhaps 1,500 shots have been fired, it will speed up. My Mark III increased from 895 to 930 with 7.9-grain Crosman Premiers in that period of time. Today, with at least 6,000 shots on it, it still goes 829 f.p.s.
A older Gamo 440 or 890 will behave like an old BSF - needing a HUGE break-in period of 3,000 to 4,000 shots to get good. But I don't think the newer ones act the same. I haven't tested enough to say for sure, but they seem to be more like the TX200.
And my experience with Diana guns like yours is that if they are going to have problems they will have them during the first 1,000 shots. They used to break mainsprings, and maybe they still do, but the spring guide now seems to be more of a problem than it was 10 years ago.
Other airguns have different break-in quirks and results, and I don't know them all. They tend to be the same for similar guns from the same manufacturer, like Weihrauch or Diana. But the minute I try to generalize, a Gamo CF-X comes along and changes everything. I love this hobby, but a lot of the fun is that nobody knows it all.