GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Bigragu on April 23, 2018, 03:41:42 PM
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Hey, all. Have a couple of quick questions regarding the gen1 to gen2 bolt swap, in this case for my 25 synrod. First off, I deeply apologize if this is an old news topic, but I just recently got into PCP’s.
Is the gen1 to gen2 bolt swap a recommended mod? In hopes to open up air from the transfer port? All the searches I’ve done show a 50/50 pro and con report on it, so that is why I’m making sure.
The bolt lugs on the gen2, are they easily adapted to the gen1 bolt, or do I have to also purchase the lug part s for the gen1? I am right handed, so no concerns about hindering myself with bolt handle placement.
I have part numbers in hand, and getting ready to call and order from Crosman. Just wanted one more check from you all.
Thank you much
Bigragu
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If you purchase a current GEN 2 bolt from crosman, it should be the current design PIN type pusher.
Tho not sure if Gen1 / 2 are a direct interchange ???
wait for further input ;)
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Thanks, Motörhead. One of these I’d like to meet you, lol. I’m just down the street from you in auburn, CA
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Thanks, Motörhead. One of these I’d like to meet you, lol. I’m just down the street from you in auburn, CA
Come over some time for our Monthly FT matches ... we have a few that join us coming out of grass valley area.
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Thanks for the invite. It’s gonna be a few months before I undertake anything like that as I just had my T9 to tailbone vertebrae all fused. Good times, lol
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The gen1 and gen2 breeches are for sure not interchangeable. As for the bolt itself, it seems you should be able to look up the part number in the gen1 and gen2 schematics, which I assume are still available for download from Crosman. If the part numbers are different, I would assume they are not interchangeable. It wouldn't make sense for them to stock two parts with negligible differences.
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The gen1 and gen2 breeches are for sure not interchangeable. As for the bolt itself, it seems you should be able to look up the part number in the gen1 and gen2 schematics, which I assume are still available for download from Crosman. If the part numbers are different, I would assume they are not interchangeable. It wouldn't make sense for them to stock two parts with negligible differences.
Thanks, Mark. Yes, I already have the part numbers in hand, ready to order from Crosman, I just wanted to get more feedback to see if this was a a worthwhile mod in gaining more air thru the transfer port passage to pellet skirt(my TP has already been ported and upsized to the Hill HFTP).
The gen1 bolt differs in design from a gen2 bolt, and both have different part numbers.
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Go over to the Marauder forum ... http://www.marauderairrifle.com (http://www.marauderairrifle.com) and do a search, i have read this subject before !!
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I tried going the other way (putting a Gen 2 bolt in my Gen 1 .25 cal marauder), and I can tell you that they can be swapped, with a few caveats. Of course I am looking at it from installing them in a Gen 1 breech so it might be different the other way around . . . .
My gun shot better with the Gen 1 lug so I went back to it, and everything that follows is just from my memory from several months ago - so it might not be perfectly accurate. And if somebody has advice going in the same direction you are offers it up, take it over mine.
First, the Gen 2 cocking lug that goes into the bolt will be too long in your gun (based on mine being the other way around). I think you should order the Gen 1 lug parts, wich really amount to a cap screw and a spacer. The good news is that the spacer is really just a bit of ~0.25" OD pipe, and the length in Gen 1 is 0.231" long, and you can make one shorter or longer as needed. The Gen 1 lug is also wider than the Gen 2 lug.
Second, the two lugs will seat pellets to different depths in your barrel, as the Gen 2 is longer overall. The tip of the Gen 2 bolt would not clear the rear of the Gen 1 breech unless it was manually retracted all the way, and I needed to do this to get the mag in each time.
In the end, even with the Gen 2 bolt brobe turned down to about .115", the Gen 1 bolt probe (cleaned up and polished) gave me about 5 fps more than the Gen 2 bolt probe, so I went back to the original.
Hope that helps some . . . you will have to fiddle with it to get it right. They fit but are not direct swaps. Others have done what you want to do, and the Mararuder forum has more info on it.
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I installed a Gen 1 bolt into my Gen 2 .25 Marauder.
When I purchased mine, both were available from Crossman. Separate part numbers. This was about a year or so ago. The Gen 1 was more expensive, at around $30. The ONLY thing I changed, was the bolt.
It bolts right in. However, it won't be clocked just right. I did some 'porting' on the bolt to get it to open up to the full area of the transfer passage in the barrel. When finished, the airflow path was uninterrupted, and was also guided by the shape of the bolt face.
Tested back to back against a Gen 2 bolt that had been turned down, the modified Gen 1 did show an increase in velocity of around 5-10 fps.
Drawbacks...
It did need modified to work to it's potential. I wouldn't do it as a direct swap.
The bolt pushes on the skirt of the pellet, instead of the hollow center. This can damage the skirt. The modifications need to be done with this in mind. You don't want to make the end of the bolt too sharp, or take too much of its diameter away, or it can damage the skirt while chambering the pellet.
It's a fun project. It's not that difficult. You simply close the bolt, and look at it through the air port, and see where it overhangs... remove, and grind accordingly until you're satisfied. I may have had an hour or so in it.
Good Luck!
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Thanks, all. After much thought, and the gain of only 10 FPS, I’ll more than likely stay with the OEM gen2 bolt. I may order a second gen2 bolt, and do the dremmel on that as some have done successfully, and if I screw that task up, I’ll have my original one to keep shooting with.
Thank you!
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Thanks, all. After much thought, and the gain of only 10 FPS, I’ll more than likely stay with the OEM gen2 bolt. I may order a second gen2 bolt, and do the dremmel on that as some have done successfully, and if I screw that task up, I’ll have my original one to keep shooting with.
Thank you!
It's hard to turn the Gen 2 bolt down to a smaller diameter. The handle does NOT come out, and there's very little room on the end to chock it up in a chuck to hold it. Some 3-jaw chucks can hold it, with the bolt handle in the space between the jaws. I have a feeling you'll make a mess out of it using a Dremel if you try to make it look like one that is turned down on a lathe, but you may be able to do some decent contouring.
I was going to mount the Gen 2 bolt in a drill press, and use Emory/sand paper, and simply sand it down to the diameter I wanted, but I couldn't get it fastened in the chuck, as the bolt handle was in the way. I ended up sending it to Travis, and he did a fairly quick turnaround with it.
Good Luck!
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Good call! Never thought about sending it off to be done. Thanks