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Discussion Starter · #1 ·
Can't find hardly anything on this. Is it a major drawback to use 2 1/2 " 65 or 67mm carts in an overbore o/u? Hunting.

E.g. Eley Grand Prix high velocity fiber in a Blaser F16.

Is there significant loss compared to using a 70mm case?

I've no preference for the shorties, just happen to have a few boxes. Curious about the physics...
 

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Why would it be different from shooting a 23/4” shell in a 31/2” chamber shotgun? The fiber wad should be fine
 
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Depends upon bore size ie degree of overbore re sealing efficiency with fiber wads….depends a bit upon fiber wad and wad stack as well, to me.

Fit & Try, eh?
 

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Discussion Starter · #5 ·
Thanks all. Was just wondering if there was any rigorous actual testing ever done or if there were any precise hypotheses about it. Couldn't find any. Like, " a 2 3/4" catridge will function marginally or significantly better ballistically in a 3" chamber compared to an otherwise equal* 2 1/2" cartridge"

* as equal as possible as there may be other moderating factors due to volume constriction.

I know about fibre wads and this seems to be more significant than length of shell (although often not much of a muchness anymore)

But when there's a 67mm fibre wadded in a 3" chamber, is that worser ;-) than a 70mm fibre?

Apparently my gun spec has this, but it means nottin' to me.

“Overbore” internal diameter of 18.65mm (0.735")
 

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Discussion Starter · #6 · (Edited by Moderator)
For clarity I should have mentioned the obvious. I'm trying to picture the shorter shells behind longer forcing cones because of the overbore.

Apparently the germans designed my gun top to bottom for steel shot. It's proofed to the max.
 

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Bog, welcome to SGW. Which part of The Oul' Sod are you from? My lot are all from Carlow and Dun Loagaire.

“Overbore” internal diameter of 18.65mm (0.735")
From memory my AL391 was .732". I put everything through that gun from 50g ITM to 25g low recoil stuff and it never missed a beat. That included Eley Grand Prix fibre, Gamebore fibre, and some ancient felt home loads. I never noticed any loss of killing power with the fibre wads (mostly on wood pigeon) at normal distances, say 25 - 40 yards .

I never pattern tested or felt (groan) the need to, but I think you'll be fine.

PS .... Basteraud, singular, as below
 
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Discussion Starter · #8 · (Edited)
Bog, welcome to SGW. Which part of The Oul' Sod are you from? My lot are all from Carlow and Dun Loagaire.

From memory my AL391 was .732". I put everything through that gun from 50g ITM to 25g low recoil stuff and it never missed a beat. That included Eley Grand Prix fibre, Gamebore fibre, and some ancient felt home loads. I never noticed any loss of killing power with the fibre wads (mostly on wood pigeon) at normal distances, say 25 - 40 yards .

I never pattern tested or felt (groan) the need to, but I think you'll be fine.

PS .... Basteraud, singular, as below
Thanks Eugene, I'm a good bit wesht of those. Co. Limerick.

I have patterned quite a few carts at different ranges a couple years ago 1) beacuse I was curious. 2) "They" say one should. But this was all 70mm clay and bird rounds (and a couple 76mm Alphamax magnum 46g BB...to be sure to be sure). It wasn't too scientific and I never compared fibre vs plastic in the same make and model. Gamebore fibre 5s and 6s, Eley Zeniths, Hull and Fiocchi plastic wad clays stuff, etc. All seem to pattern well in skeet, 1/4 and 1/2 choke (except some Armusa stuff I got that seemed to have some gaps and fliers. I'll give the couple boxes of that sh*te away to someone for the Corvids). I didn' t screw in the 3/4 once yet. Haven't had the need as I haven't been at any big fowl or high pheasants with this gun. Only using it on rough shooting pheasant mostly, a rare woodcock, rare sprung duck at close range and the odd snipe and some sporting clays non-competitively, but frequently.


I suppose I was looking for speculative opinion before I inevitably satisfy my OCD and actually take a couple of the Grand Prixs at some cardboard roll I have for just such purposes. It's the only way I'll know. I'm sure they'd pattern fine for the close range pheasants the dogs puts up. It just seems there'd be a bit more space for leakage with only 2 1/2" into an overbored 3" chamber before the forcing cones? I've leaned toward the Gambore stuff with the fibre quad seal. Not on substantial evidence, rather marketing and promises ;-)


I just have to fix my frame I screwed together with some thin, soft timber. This time with two legs in the back at the side! I had built it like a tripod easel with one leg in the centre back. I blew that off with the second shot of the 46g BB! Duh! Major design flaw! :-{

P.s. As a Munster rugby fan, I know that fat bastareud well, but I'll refrain from further comment rather than derail the thread topic ;-)
 

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Discussion Starter · #9 · (Edited)
My most sincere and humble apologies. I just see post #6 was mod edited for my referral to the imminent complete ban on lead shot for hunting being driven by greens in Europe and my use of a play on words to substitute a derogatory term by using a similar sounding french surname. I thought I was being careful, but we are a lot looser with foul language in Ireland. :-O
 

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Just to add, the fibre shells would have been 21/2", 65mm or 67mm. I had a supply for my SxS game gun.

I recall yer man running through Johnny Sexton a few years back. Mind you that's a tradition that still exists as demonstrated by the All Blacks in Dublin last weekend. We have a Kiwi neighbour and he's still in mourning, bless his cotton socks. I am, as you'll understand offering all the aid and comfort I can find. 😎
 
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Discussion Starter · #11 ·
Just to add, the fibre shells would have been 21/2", 65mm or 67mm. I had a supply for my SxS game gun.

I recall yer man running through Johnny Sexton a few years back. Mind you that's a tradition that still exists as demonstrated by the All Blacks in Dublin last weekend. We have a Kiwi neighbour and he's still in mourning, bless his cotton socks. I am, as you'll understand offering all the aid and comfort I can find. 😎
Indeed, that's what they were intended for. The ones I have are marked 67mm, but I only see on their website now "True 2 1/2" (65mm).

If I was lucky enough to have a classic sxs, I probably wouldn't be here on this. I'd probably have just saved it for that.

P.s. Never mind Johnny. He's Leinster. What counts is Ireland beat the "mighty All Blacks" (and quite convincingly) for the third time since 2016. 2016 being the first time ever (since 1905)!

I'm sure you know Munster did it in 1978 :cool:

(now this side conversation must be offside! I'm not sure who is more to blame for starting it, you or me ;-) but the evidence on me was deleted :cool: )
 

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Richard Atkins on over-boring and fibre wads

Report of a fibre wad obstruction with burst
https://forums.pigeonwatch.co.uk/forums/topic/382076-barrel-blowups/

Not quite on topic, but possibly of interest

No difference with 1 oz loads through .020" choke
Shotgun-Insight Express 28g Fibre vs Plastic

or with Skeet choke
Shotgun-Insight Hull 28g No9s

http://discovery.ucl.ac.uk/1382490/1/396689.pdf
The author stated that the study was not designed to evaluated different wads, but little difference was seen.
 

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Discussion Starter · #14 · (Edited)
Wow. This is one enormous website! Look what I just stumbled upon! it never came up in a Giggle search before, nor here. "Eug Molloy", you feature from 10 years ago!


Some very relevant "opinions"!

The jury is still out. I'll just have to go pattern the flippin 67mm fibre Eleys myself to know.

This was largely a curiosity. I only have slightly fewer than 100 of them and I know they're ideal for a smaller sxs...

Alternatively, there's that whole school of thought on intentionally using fibre on open chokes for the purposes of woodcock...another debate. But eco friendly carts are moving along nicely in R&D.

It was previously mod deleted as explained above, presumably for using the French surname "Bastareud" in jest, but what I was also alluding to is that the Blaser F16 was designed by the Germans with fibre wads and steel shot ('"magnum" even), probably mainly, in mind. So, I'm all set for the future when the EU takes away all of our lead shot for essentially any hunting with a scatter-gun I'll ever be doing!


Anyway, my f16 doesn't seem to be extreme in overbore or cone length compared to others out there...More specs below.

Happy to continue the discussion and let you know how the wee orange yokes pattern, but I'll likely be busy at clays and hunting at the weekends in any of my spare time for the foreseeable. Having a job, and the small hike required to pattern, I may not get to it soon, or ever....
:cool:

Blaser F16 Game | Shooting Sportsman

The bores had 3" chambers, then long 3" forcing cones to slightly overbore .732" barrels. There was a clearance jump out to .745" at the rear of the screw chokes before the tapers began.

The screw chokes supplied are flush mounted and 2" long, looking very much like the old Beretta Mobilchokes. But there is a difference. Beretta’s chokes are threaded at the front, while Blaser’s are threaded at the back. While there are no problems with either, I think that rear threading is better and could better forestall carbon seepage and buildup. The chokes are notched on the front edge, to engage the supplied choke wrench.

Three chokes were included: Improved Cylinder, Modified and Improved Modified. The IC had .005" constriction, not the usual .010". The interior was all taper with no parallel. The M had .017" constriction, a touch less than the normal, with ¼" parallel after the conical section. The IM had .020" constriction, about usual for Modified, with ½" parallel. Note that as the chokes tightened, the parallel got longer, to stabilize the shot. Other choke constrictions as well as extended chokes are available on request. All of our chokes were listed as being suitable for steel shot. Barrel bores are chrome plated, which makes for easier cleaning....
 
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