Theoben Rapid Forum

Everything Technical About Rapid => Technical => Topic started by: Topsparx1 on September 15, 2020, 07:14:01 PM

Title: 12 Shot Mags and Accuracy
Post by: Topsparx1 on September 15, 2020, 07:14:01 PM
Can someone explain to me how a 12 shot magazine can alter accuracy. Ive got Dr Bobs mags and Ive been testing my Rapid 7 Mk1 accuracy today. At least one shot out of the 12 went off target sometimes more, it wasn't me as I was bench resting and it wasn't the pellets Webley Accupell 14.3grn cos I checked and weighed them for each mag fill. The barrel is clean also. My understanding is that the pellet probe pushes a pellet out of the mag and into the barrel when cocking the rifle so when the pellet is fired the magazine is not even in play so how does that affect accuracy ??? Please help, Ive spent a small fortune getting this R7 up to scratch and its very disheartening for this to happen. I'll be testing again tomorrow with a chrono as Ive had a KevG reg and a Dr Bob QF unit fitted, just to see if I'm getting consistent air delivery.
Title: Re: 12 Shot Mags and Accuracy
Post by: Remchester on September 15, 2020, 07:27:55 PM
I'm no expert but I've heard the mags can be wound a bit tight and can damage pellets when rotating also some of the holes for the pellets can be slightly tight and cause them to sit differently in the mag and mess with things also sure some one will be along with a bit more detail
Title: Re: 12 Shot Mags and Accuracy
Post by: bob4026 on September 15, 2020, 08:20:36 PM
Isn't there a small amount of sideways load exerted by the mag spring as the probe travels thru the mag? If so there may be an odd occasion when there is skirt damage?

I presume all is well when you single load?

Bob
Title: Re: 12 Shot Mags and Accuracy
Post by: KevG on September 15, 2020, 10:21:12 PM
are you sure its mags.have you tryed singal loading.have you tryed with out silencer.
KevG
Title: Re: 12 Shot Mags and Accuracy
Post by: Ca_Varminter on September 15, 2020, 10:33:12 PM
I have different Mags for each type of pellets I use most often.
You want the tension adjust the the lowest setting that will still advance all the pellets reliably!
This is to keep the chances of deforming the pellet to a minimum.

Heavier pellet will require more tension than the lighter one.
But the Heavier Pellets have thicker skirts!
So they can take a little more tension without deforming!!

Stuart

Btw.. for Benrest testing, I use a single shot tray...for Maximum accuracy potential
(https://photos.imageevent.com/scl_electronics/gun/ultimaterapid/websize/rcm-ss5.jpg)
Title: Re: 12 Shot Mags and Accuracy
Post by: Topsparx1 on September 16, 2020, 09:08:42 AM
I haven't tried single loading as I wanted to test out the new mags from Bob, they are very tight to push in but I don't want to start adjusting the barrel yet as KevG set it all up for me with a Dr Bob mag that I sent him. The two new mags must be a slightly thicker dimension cos they're really hard to push into the slot. I will try single loading today and see if there's a difference, as the mags are new they could need a bit of setting up then with the tension of the spring etc, I thought they would be set up right straight out the box but maybe not
Title: Re: 12 Shot Mags and Accuracy
Post by: Topsparx1 on September 16, 2020, 06:46:11 PM
OK so Ive done some single hand loading shots and they are as bad as the mags, some good some bad. The very tight fit of the mag into the action was caused by the barrel being a fraction too far back into the magazine chamber so that's now fixed. I had to remove the scope to do that and now the scope is back on the gun I don't know what's going on. Its now shooting a foot low and a foot to the right. I cant get enough adjustment on the scope to correct it. I have no idea how to fix this help me out guys please
Title: Re: 12 Shot Mags and Accuracy
Post by: Remchester on September 16, 2020, 07:22:37 PM
Quote from: Topsparx1 on September 16, 2020, 06:46:11 PM
OK so Ive done some single hand loading shots and they are as bad as the mags, some good some bad. The very tight fit of the mag into the action was caused by the barrel being a fraction too far back into the magazine chamber so that's now fixed. I had to remove the scope to do that and now the scope is back on the gun I don't know what's going on. Its now shooting a foot low and a foot to the right. I cant get enough adjustment on the scope to correct it. I have no idea how to fix this help me out guys please
You may have canted the barrel when you moved it bud. Loosen it off again nip up the location screw first just enough to keep the barrel in the right spot for the mag then nip up the pinch bolt a bit then tighten down the location screw then tighten the pinch bolt but dont go mental on them mate 👍
Title: Re: 12 Shot Mags and Accuracy
Post by: Remchester on September 16, 2020, 07:28:06 PM
Also buddy just looked at the pics of the rifle is the silencer touching the buddy bottle at all? It looks close on the pics but cant tell for sure?
Title: Re: 12 Shot Mags and Accuracy
Post by: KevG on September 16, 2020, 08:53:07 PM
what scope rail do you have on.some of them will not alow the mag to go fully into place and need a little removing.i thought the bottle looked like it was touching silencer but hard to tell in pictures
KevG
Title: Re: 12 Shot Mags and Accuracy
Post by: Topsparx1 on September 17, 2020, 08:53:14 AM
Thanks guys I'll redo the barrel screw and pinch bolt to see if that's the issue, it may be as it wasn't shooting like that before I moved it 🤦🏻‍♂️ The scope rail is from Best Fittings Kev and doesn't seem to foul the magazine ?? The silencer is close but definitely not touching the buddy bottle there is a 5mm gap between the two. The silencer is one of Pete Burtons (bucketboy) it is really good for sound but I cant get it to tighten enough to stop it from twisting on the barrel. Its a slip on reflex type that is a really tight fit and goes on about 50mm so theres no movement in it to cause clipping and I looked at the hole on the end and there has been no contact as it is still as new. Oh well guess Id better get up the shed and start tinkering.
Title: Re: 12 Shot Mags and Accuracy
Post by: KevG on September 17, 2020, 01:26:00 PM
I would try it with out silencer just to double check..they don't always have to clip to be thrown out.not being tight would concern me.
KevG
Title: Re: 12 Shot Mags and Accuracy
Post by: Topsparx1 on September 22, 2020, 04:59:07 PM
So finally got around to sorting out my problems, firstly KevG the silencer is tight on the barrel in fact its a very snug fit, and its not touching, I found the problem to be the way I had refitted the barrel and scope after moving the barrel back a touch. Having gone right back to scratch and refitting everything correctly and re-zeroing the aim is now spot on. Pellet on pellet with the rifle in a fixed position, 12 shots within a 5p coin at 30yards using a bipod and rear bag, that's good enough for me. Very pleased with the JSB Strattons and Hades that I used much better than the Accupells I was using. Thanks for all your help and comments guys 👍🏻
Title: Re: 12 Shot Mags and Accuracy
Post by: Remchester on September 22, 2020, 05:48:54 PM
Quote from: Topsparx1 on September 22, 2020, 04:59:07 PM
So finally got around to sorting out my problems, firstly KevG the silencer is tight on the barrel in fact its a very snug fit, and its not touching, I found the problem to be the way I had refitted the barrel and scope after moving the barrel back a touch. Having gone right back to scratch and refitting everything correctly and re-zeroing the aim is now spot on. Pellet on pellet with the rifle in a fixed position, 12 shots within a 5p coin at 30yards using a bipod and rear bag, that's good enough for me. Very pleased with the JSB Strattons and Hades that I used much better than the Accupells I was using. Thanks for all your help and comments guys 👍🏻
Happy its sorted mate! Not fun when you put em back together and find it's not the same as before ask me how I know!🤣🤣👍👍👍
Title: Re: 12 Shot Mags and Accuracy
Post by: Dr Bob on October 30, 2020, 05:15:55 PM

The last difficult one I had to sort turned out to be a tiny spot of rust in the middle of the barrel. You got around 10 shots that were on target then a flyer. The pellets were depositing lead on the rust spot then every now and then  the next pellet would pick the deposit up and cause a flyer . Solvol Autosol chrome polish on a mop sorted it ;)

Bob