Do pellets need to be “barreled-in”? Airgun Science or MYTH?!

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JungleShooter

JungleShooter

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Do pellets need to be “barreled-in”? Airgun Science or MYTH?!



I’m getting for my first serious pellet test for a new gun. Now all those things come up that I’ve read over the past couple of years in the forums. And I need to make a decision. Maybe you can help me dispel an urban gun-myth, or prevent me from messing up my pellet test (which really depends on this particular issue, I will explain this in a separate post).

The issue is that pellets need barrelling-in – meaning that the barrel rifling needs somehow to get used to a new pellet.



Here are some quotes from important voices. What do you think?



● AirArms (UK): “Make sure you give each brand enough shots to settle down in the barrel before committing the results to paper.”
https://web.archive.org/web/20161221142502/https://www.air-arms.co.uk/academy/161-picking-the-right-pellet



● Prometheus Pellet Manufacturer (UK) – the inventor of the now renamed H&N Sniper series: “Important: Please allow at least 30 shots for the barrel bore to settle when changing from a different make of pellet.”
In another place they recommend 50 shots.
https://web.archive.org/web/20130808121409fw_/http://defiantpellets.co.uk/faq.htm



● Phil Bulmer, airgun writer (UK): “The usual 40 or so ‘barrelling-in’ shots were fired; I expended these at paper targets and certainly witnessed a settling in period. Initial groups from the first batch wandered around before settling into coherent patterns – so clearly you need to give this round time to come good if you switch to them.”
Source: Phil Bulmer (2014), in Airgun Shooter, in an article on Webley Accupell FT pellets [H&N FTT rebranded], part of a series of testing pellets.
https://www.blackrecon.com/articulos/Balines-Webley.pdf
Again, same author:
“I fired about 40 shots to let the barrel ‘adjust’ to the new ammo before commencing testing. This is an important part of the test and, in the Diablo’s case, the running-in process was much needed; the group sizes markedly shrank from the early shots I fired.”
Source: Phil Bulmer (2014), in Airgun Shooter, in an article on Brocock Super Diablo .177 pellets, part of a series of testing pellets.
https://www.airgunmagazine.co.uk/tests/brocock-super-diablo-177/






Please, state your opinion, and name your reasons and supporting evidence:
[1] Airgun myth
[2] The truth and nothing but the truth
[3] Regional pellet debilitating virus (you notice: all writers are from the UK, and this barrelling-in debility virus has not jumped over the Atlantic to the US)
[4] Regional ignorance (in the UK this is common knowledge, but US airgunners as of yet are ignorant of this)
[5] Only matters for the sub-12FPE guns of our poor British airgun friends who are suffering under exaggerated laws – doesn’t matter to US airgunners because in the US the magnum fever reins
[6] ................................?



Seriously, I’m serious about this. My pellet test design stands or falls with this barreling-in issue.
Thanks,
Matthias


 
I don’t think the smooth twist and smooth twist X need is as there are no groves cut inside the barrel they are on the outside of the barrel and don’t come in contact with the pellet. I know of some who will hone the inside of barrel by wrapping a dowel with fine sandpaper and spinning the barrel in a lathe. I’ve broken in some of my long range 308 and 6.5 creedmore barrels using bullets that were coated with an abrasive grit using Tubb projectiles.

https://www.midwayusa.com/product/1006409224/tubb-final-finish-bore-lapping-system


 
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Matthias,

Whenever I test different types of pellets in my rigs, I will shoot a bunch of "fouling shots" usually no more than 30. More importantly, I clean the barrel between brands thoroughly before I go to the next pellet. I shoot 12 ft lb exclusively here in the US. This process has been relayed to me from numerous elite shooters, tuners, and smiths.

Tom Holland 

Field Target Tech 
 
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Mmm, if Ed of EdGun fame says it, it must be true. 😎

Aaah, I like the guy a lot, and his guns are super cool. And Tom Holland has weight, too.

But an explanation WHY this might be so, that's what persuasion is made of....



Thurmond (T3P Ranch), your post has more weight here, at least for me. You actually give an explanation: "Lead is deposited in the barrel which helps in some situations to make minor imperfections in the barrel inner surface and rifling "smoother". Much like lapping a barrel does for firearms (which coincidentally works for airguns too). "

That makes good sense to me -- after I clean the barrel I'd want to cover the surfaces with a layer of smoothening lead. Cool. But what writers meant to say is that after the barrel has shot say 60 JSB Heavy 18.13gr and you want to switch pellets to JSB Domed 15.88gr — you must shoot 40 JSB Domed before any real accuracy happens — because, I guess, "a Heavy leads the barrel differently than a Domed."

So they seem to think at least, without saying it in so many words....



Now, if someone has an explanation for this case as well, I'm open to hear it.

I'd really like to get to the bottom of this. Myths and traditions are great fun for story time at the bonfire, but when they cost me 40 wasted shots every time I want to switch pellets, mmh, not so much. Thanks for helping all of us clear this up. 😃

Matthias


 
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The way the professionals test for “absolute best” pellet is shoot 10-30, then start testing for accuracy indoors or a tunnel. 

They then clean barrel & repeat with next prospect due to different materials/hardness of lead.

I’ve bought many a spring gun that just needed to be cleaned, leaded up with right head size & weight, brand, and tried various holds. Tighten screws. Once tuned by someone who knows way more than I about tuning spring guns, the difference to me was well worth a $250 tune & shipping. I can tune my PCP’s but I know nothing about fitting seals or best spring for smoothest shot cycle, the math of swept volume. I understand what they’re fixing/improving but I’m no spring gun tuner. 
 
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To somewhat parrot the post just above this one ... Leading "sizes" the bore for the individual characteristics of the particular type / brand / dimensions / alloy of the pellet being fired. It stands to reason that if there is a change in pellet dimensions or other characteristics that the bore must "resize" to the new projectile.
 
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So I had never heard of this "myth," however I did independently discover it. Let me elaborate: 



Back when I got my first serious PCP, an AA S510, I was shooting JSB 18.13s and Crossman Premier HPs. The CPHPs weren't as accurate, but were about half the price of the JSBs, so I shot them when I was just shooting for goofs and switched to the JSBs when things mattered. But for some reason, in that quick switch, the JSBs didn't seem to perform initially as I'd expected them to. So I came up with the idea that, as crazy as it sounded, maybe the barrel needed to lead up with the same lead as the pellet. Now here is an important note about that: while I can't speak for this between other pellets, the CPHPs are comparatively VERY hard, they seem to have a high alloy content and are significantly different from the JSBs which are quite soft presumably almost pure lead. If I had a guess I'd also say that the CPHPs are also probably cast while we know the JSBs are swaged. Differences in lubricant on the surface may also be a factor here. 

Either way I performed a test to see if I was crazy or not, and sure enough when switching from CPHPs to JSBs accuracy substantially improved over the course of 2-3 dozen shots. Now a couple things to note about this. First is I only tested in one direction, that is to say going from CPHPs to JSBs. Second, I only tested one gun with one barrel. Third is I don't have any evidence for the mechanism of action, which sounds like it is what you really want JungleShooter. 

As an aside I noticed a similar phenomenon when (again) going from CPHPs to JSBs in my FX Crown with the STX barrel, however I just chalked it up to being the same phenomenon and switched over to shooting exclusively JSBs and didn't think much more of it. So I have no empirical data for the STX barrel. I will say though that the inconsistency in the CPHP head sizing was very noticeable in the STX barrel, and was reflected in the group size as well. ;) 

Of course there is plenty of reason to be skeptical. I don't still have documentation from the testing, I don't have an explanation for why, and on top of it all I'm just some random dude on the interwebz. So what do I know? If you're looking for answers though, I think short of spending an afternoon gathering data and then doing a statistical analysis to break it all down and determine significance, this might be as close as you're going to get. That is to say various people's anecdotes of having observed the phenomenon. 



I hope that helps. :) 
 
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I was shooting my .22 Colibri earlier this week. I normally shoot the 18 gr JSB's with it, but for some strange reason I decided to try a magazine of the Crosman 14.3 gr domed ultra mags.

I noticed they didn't load into the magazine as smooth as the JSB's and the cocking wasn't anywhere as smooth either. They just seemed to be a lot tighter fit in the breech than the JSB's? The Crosman groups were no where near as tight as my JSB groups. So I quickly said the heck with that.

Since I had only shot the one magazine 14 rounds, I went right back to JSB's without cleaning the barrel. Noticed right away my JSB groups had opened up after shooting the Crosman's? Took a couple of magazines of JSB's before the groups tightened back up.

Kind of reminded me of how it takes a couple magazines to get back in the groove after a barrel cleaning? Maybe I can just shoot the Crosman's to clean the barrel? LOL

Fuss




 
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Posed a similar question a week or so ago. Doing a bit of RF checking for groups with several brands and quality within a brand. Would pull a patch or two the shoot several rounds to reseason the barrel before shooting groups. Quite a difference. I found with shooting groups over the last week I have been shooting until I see the group's start to shrink then shoot for record. HAVE found, some brands have a lube some don't. I am seeing POI change during seasoning and group size.
 
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I don’t think the smooth twist and smooth twist X need is as there are no groves cut inside the barrel they are on the outside of the barrel and don’t come in contact with the pellet. I know of some who will hone the inside of barrel by wrapping a dowel with fine sandpaper and spinning the barrel in a lathe. I’ve broken in some of my long range 308 and 6.5 creedmore barrels using bullets that were coated with an abrasive grit using Tubb projectiles.

https://www.midwayusa.com/product/1006409224/tubb-final-finish-bore-lapping-system

Click to expand...

This is interesting to me, and I don't know enough about "smooth twist" to have a good view on the subject.



Is smooth twist polygonal rifling like we see on glock, and some older CZ, or is it more like the "smooth twist" we see on guns like Marlin with their model 60 and some of their center fire offerings?



I can say that you can lead up the marlin system....and when you do things go to ______ very quickly. The Polygonal system is very forgiving in the cleaning area....it has also been called the "canted" system and is used on some VERY high end rifle barrels. They are generally thought to provide a better seal so you get a bit more FPS out of them as well.



As I understand things polygonal is expensive to make, puts tons of heat into the barrel, so you need more care in the heat treatment of that barrel....not a big thing when talking pellet rifles, but for center fire rifles....ah yea.



As to the "myth". I really think that a gun....really any gun gets use to a projectile.....be it a pellet or bullet. And I have notices in working up loads for fire arms changing the bullet tends to send things off into left field. I think that everyone has a different formula for the jacket, or lead in the air gun world....and switching without getting the "old" out is not going to give you the "best" result.



Yea and I am really board so here I am again.
 
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1559949358_7405449635cfaf02e4c9d76.25065766_5D2A215A-9DE2-49B7-BEB9-10194788C154.jpeg


I posted this picture a year or so ago. I had just cleaned the barrel on my Walther LGV 22 cal with a brass pull through and dry patches. I recall I had changed pellets to H&N FTT. In my case I can clearly show how accuracy returns after cleaning and changing pellets. I have had similar results on my other springers but not so dramatic. I think the distance was either 25 or 30 metres.

Gary
 
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...shoot , i thought you meant seating the pellet into the barrel or rifling........ after better understanding what the heck i'm adding here, i find the same thing you gys mentioned. only i call it "seasoning a barrel" . much like one would season a cast iron skillet with oil over time. have to get it leaded up again and i find it takes around 50 shots to get most barrels to act right for after a thorough bore cleaning. i dont clean those unless i have to anymore. a cleaning felt or wad or whatever cleaning pellets are called, seems to work fine for me. jsb pellets are way softer than the hardened crosman pellets. i heard they use antimony to harden them. the .20 exacts work fine from springers, but most .22 jsb's lose velocity , in magnum spring / pisto guns anyway. i think the force either blows the skirt or somehow air flys by the pellet, or around it in the barrel. i generally use jsb's in pumpers, co2 and hpa airguns. except that thick bodied 13.7 grain .20 jsb exact, and the 25 grain .25 cal pellets in my .25 gamo big cat (use them in in my co2 .25's, too.) ........ with those mendoza air rifles, we had to blow the smoke out of the barrels or we would get flyers. those are made to diesel, but it's too inconsistent. .............but as far as barreling in a pellet - i find that my shots are more accurate when the pellet is somehow seated into the rifling....kind of like the difference between a 1389 backpacker / or crosman ssp250 pistol vs. a 2400kt with extended bolt probe from charles mellon or alchemy. the loading clips on those older crosmans (262 rifle had one, too) - they were a bad design. if they werent closed all the way, the pressure would usually cause your plastic clip to go flying about as it broke the ears the seated it into the gun. the ssp250 / 262 rifle valves are more powerful, tho. just could have been more accurate and easier to load for a silohette pistol. - paul.
 
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