Fiocchi Slugs, Stock Fit & Barrel 'Bending'

[flyfishdave]

With the New Holland/Topton 2-Gun match series starting this weekend and a TTI tuned Benelli M2 completed, I finally finished slug/choke testing and POA/POI determination.

Last week’s test parameters:

TTI M2, 24” barrel

Fiocchi Exacta Aero ⅞ oz and 1 oz slugs (2 ¾” metric inches)

⅞ oz @ 1300 fps, 1 oz @ 1150 fps

25 and 50 yards

Briley extended IC and LM chokes

Small gel pad, 13 ⅞” LOP

‘C’ drop shim/stock plate, 65mm drop @ heel

5 shot groups - may have fired 6 in one, and 4 in another @ 50 yards

***all shots standing, unsupported***

@ 25 yards, both the 7/8 and 1 oz load with IC was hitting about 4" high and 3" left

@ 25 yards, using a LM choke, both loads hit about 4" high and 2" left

@ 50 yards, the 7/8 and 1 oz loads using BOTH the IC and LM chokes hit about 6" high and 6" left

25 yards, ⅞ oz, IC:

25 yards, 1 oz, IC:

25 yards, ⅞ oz, LM:

25 yards, 1 oz, LM:

[flyfishdave]

50 yards, ⅞ oz, IC:

50 yards, 1 oz, IC:

50 yards, ⅞ oz, LM:

50 yards, 1 oz, LM:

Both the ⅞ oz and 1 oz slugs behaved in similar fashion; the LM choke appeared to be an inch tighter @ 25 yards. General impression was that the ⅞ oz slug had more of a slap to the face feel while the 1 oz was more of a solid push. I did get a nice welt and the stock actually cut my cheek and drew blood after 15 rounds.

While the POI/POA variance and face battering was likely due to a poor gun mount and not having shot any clay games in 3 years, the consistency in POI was likely due to stock fit. I noted that all my trap guns have their combs pushed all the way to the right to accomodate my melon sized head.

Based on the results above, I needed to move POI to the right and down to get POA to equal POI, or at the very least, much closer than above.

[flyfishdave]

The Benelli ‘C’ drop shim/stock plate (used in the first test firing) positions the stock for the greatest drop, and Benelli does not have another shim for more drop. Without a shim to increase drop at heel beyond 65mm, my only option was to use a thicker pad for a longer (½”) LOP. Since the comb is angled downward from receiver to pad, a consistent mount with a longer pad/LOP should drop the POI.

For windage, I ordered a cast shim. For some reason, mine did not have one and looking at it I can see why it is easily missed. The DX/SX is as thin as a razor blade, but looking closely, one side is appropriately thicker to create cast off or cast on. This was installed for cast off (DX) to move my POI to the right.

Today’s test parameters:

TTI M2, 24” barrel

Fiocchi Exacta Aero ⅞ oz and 1 oz slugs

⅞ oz @ 1300 fps, 1 oz @ 1150 fps

50 and 100 yards

Briley extended LM choke

Regular gel pad, 14 ⅜” LOP

‘C’ drop shim/stock plate, 65mm drop @ heel

‘DX’ cast off shim

5 shot groups

*50 yard shots standing/unsupported and seated on bench, shotgun/arm on range bag*

*100 yard shots seated on bench, shotgun/arm on range bag*

50 yards, ⅞ oz, LM:

50 yards, 1 oz, LM:

100 yards, ⅞ oz, LM:

100 yards, 1 oz, LM:

For the 50 yard targets, the bottom group was shot standing, unsupported. I tried to hold POA around the lower ¼ of the orange but knew the gun was moving all over the place. I could not make out a nice tight group (forgot the binoculars) so decided to remove the ‘indian’ from the equation and rely more on the ‘arrow’ to determine POI. The top groups (head shots) were shot seated, using a range bag to support the arm and fore end, and had the top tip of the green HiViz TriComp triangle cover the nice group for both the ⅞ oz and 1 oz loads.

I also ditched the hand drawn circle with black hash marks and instead, cut out a stencil and spray painted the target. Stencil is cut to ‘BC’ size steel to give you an idea of group size. Both the ⅞ oz and 1 oz slugs hit consistently, and there was no significant difference between both loads when compared to last week’s test, while standing, unsupported @ 50 yards.

Increasing the LOP with the thicker pad and using the DX cast off shim definitely worked as intended, dropping the POI and nudging the POI to the right. Another unintended consequence of tweaking the stock fit was reduction of perceived recoil. Now, both the ⅞ oz and 1 oz slugs have an identical feel. Last week, my preference would have been for the 1 oz load, but now, I can say both felt equally good as a slug can feel. I only fired 30 shots, but no welt and no cut to the face today.

The 100 yard targets were also shot seated, off a range bag. As best I could, the TriComp front sight basically covered the orange filled BC zone. It was drizzling and the mirage off the hot barrel and new RX for distance vision were not helping either but I’d say that the ⅞ oz slug dropped about 7” and the 1 oz slug was around 9”. The only issue with these Fiocchi slugs is that they are 2 ¾” long in metric inches….basically longer than 2 ¾”. If you have a shell caddy with walls that encompass the ends, you may be out of luck. I have some AP Custom 3x3 caddys and the Fiocchis are too long and will not fit.

For anyone having POA/POI issues with their smooth bore long gun and/or considering any barrel voodoo work to correct any discrepancy, I recommend reading this very enlightening thread:

http://www.brianenos.com/forums/index.php?showtopic=181917&hl=

Kurtm started the thread and it describes the basis for his brilliant solution to correcting POA/POI issues. Basically, his technique and special jig uses science, engineering and good old common sense and logic to align the receiver to the magazine tube to ensure the barrel sits properly in the receiver after tightening down the magazine tube. No more bending barrel b/t tree limbs and whacking on tree trunks, and no need for any secret special voodoo techniques.

I only read this article after getting my TTI modded M2 back. When they assured me that they never bend any barrels in adjusting POA/POI to hit true, I was curious. After reading the above thread, it all makes perfect sense. Regardless of who does the work using Kurtm’s jig (I understand several gunsmiths in the US have his jig), what’s important is that when done correctly, you can have complete confidence that the arrow is straight and true, allowing you to then tweak and adjust other parameters (including the ‘indian’) to ensure your POA/POI is to your satisfaction. In my case, I just needed some minor adjustments in stock fit which was accomplished without much work. No need to swap out front sights, dovetailed ribs, 10/22 rifle sights, bomar pistol sights, mid-rib beads, wasted money and time chasing perfection. Now, time to practice these new load 2, load 4, quad load, duo load, no load, strong hand, weak hand, no hands and feet load techniques so I don’t have to do the dreaded drop your shells and ground load technique.

Dave

[Jadeslade]

Nice. TTI mods awesome. Had to cut one coil to get 10 slugs of Fiocchi 1oz in + 10 tube. Did you measure the 7/8" slugs? Are they a little bit longer ,too? I measured my 1oz. The Remington reduced recoil have changed so much that they are not reliable, especially the blue law enforcement ones. Amazing, really because the rest of the Remington shot I use is excellent.

[poortrader]

That's a lot of testing. I'll be at Topton too. Whenever I tested my TTI, I shot from the bench. I like the RIO low recoil over the Remington's and fiocchis.

Sent from my iPhone using Tapatalk

[Flatland Shooter]

The Remington reduced recoil have changed so much that they are not reliable, especially the blue law enforcement ones. Amazing, really because the rest of the Remington shot I use is excellent.

Please excuse the thread drift.

What problems are you having with the Remington slugs?

I bought several cases earlier this year and out to 70 yards they do well.

But trying to hit a very large target (I think it was something like 4' x 4') at 150 yards was not possible. Shot using a rest, a red dot and Cyl, IC and LM chokes.

For birdshot all I use are Remington Gun Club (for practice) and STS (for matches).

Bill

Edited March 29, 2015 by Flatland Shooter

[Jadeslade]

Not cycling, different powder loads, swelling of the crimp, not grouping. Have several different cases and lots of different lots. Of all kinds. I'd have to use a full power and practice the holdover on a plate like that. Had no misses out to 100 yds at Last Versamax #2 Match. 100 yd shots from inside a car. All others offhand. Discussed this with a lot of guys. Hardly see Remington reduced recoil anymore. Also, Walmart Federal are getting so dirty I don't want to use them anymore. Obviously different powder. Ammo companies seem to not think it is important to list changes in manufacture. Thread drift off. Nice work by flyfishdave. Hope you've fished the Letort.

[Willz]

Awesome thread, I need to do this with my TTI M2 before I shoot my next match. The last match I shot had some 80 to 90 yard slug shots on Larue targets.

Edited March 29, 2015 by Willz

[Jadeslade]

The long shots at the Versamax were Larues

[Willz]

The long shots at the Versamax were Larues

Same match, I was in squad 7.

[Jadeslade]

Ok. So muddy and rainy it was hard to tell who was where. Ended well though. Love those matches.