Tell me about pattern testing, please.

[Justin44]

Evening gentlemen, just looking for a little information please.

if you were going to pattern test your gun and load, what would the test be?

1 shot at a plate with each choke and at different distances?

how often if ever would you do this? Where? And what is the cost.

i saw a thread where someone had photoed some sheets he’d shot and then coloured each shots hit with a blue dot, is this done on a computer or software?

 

[Geordieboy]

Evening gentlemen, just looking for a little information please.

if you were going to pattern test your gun and load, what would the test be?

1 shot at a plate with each choke and at different distances?

how often if ever would you do this? Where? And what is the cost.

i saw a thread where someone had photoed some sheets he’d shot and then coloured each shots hit with a blue dot, is this done on a computer or software?

I am an engineer. So by that very need to understand, wished to see what cartridges gave the most even patterns. 

Why? Because shooting L.F. and Full through my Perazzi splits Clay's instead of dusting them. 

I chose 8 cartridges. I shot 2 different guns from 1/4 through to full choke at 38m. I painstakingly counted each shot and coloured them in. (Yes I know). Then, having ascertained the shot count on each cartridge, worked out the percentage within the 30" circle.

I learned this;

L.F. & Full choke in the perazzi were awful, with less shot in than half choke. 

Full in the 725 Browning was the same but with loads of holes......no matter the cartridge I used.

3/4 in the perazzi gave a density of 85% 

3/4 in the Browning 80%

I also discovered that Eley Titanium shells whilst maintaining the same density, were tighter by some margin. 

I also discovered that both guns shoot where I look and that was most satisfying.

Pattern closer if you wish, but I suspect the only real difference you'll see in pattern size is with Cylinder. At 10yds, the pattern hasn't had time to develop. 

 

[Doctor Lecter]

so many variables    ,    check it out on youtube , plenty of vids to watch ,

 

[Salopian]

Traditional Patterning is done at 40 yards to check percentage of pellets from a full load that are distributed inside a circle of mass density on the pattern board or pattern paper . To get a true record you need to fire 10 cartridges at the same distance through the same choke constriction.

To check for Gunfit you do the same tests at 16 yards , the deviation from where you aimed is calculated as for every 1"inch off the point of aim at the pattern requires a 1/16" inch adjustment at the face of the comb of the stock .

To pattern for effectiveness at your preferred range of shooting ( ie decoying pigeon) shoot at that range and choose you most effective choke / cartridge combination.

 

[Westward]

if you were going to pattern test your gun and load, what would the test be?

People test for 2 very different things. Firstly, point of aim v point of impact (POA/POI). Yep, some people really are that anal especially in America where they can't seem to fully separate shotgun shooting from rifle shooting. I tried POI testing once and found that the barrels on that particular gun didn't shoot to the same place and  as my brain couldn't cope with the thought of allowing for it the gun had to go.

I haven't done much pattern testing either but I've done enough to explain why so many experienced sporting clay shooters throw in 2 x LM or 2 x M and just leave them in. The distances were 25, 30 and 35 yards. Shooting off the shoulder with the usual shells and moving the gun to the target (a 4 inch X) rather than shooting with a dead gun. All I checked for was the evenness of the spread in a 30" circle as life's too short to count pellets.

The net result is that since then I've never shot sporting with anything tighter than M and nothing more open than LM.

 

[ips]

Imo pattern testing is exactly that, poi / poa is best evaluated on a DTL type target were gun speed and other factors enter the equation. From my experience (40 yrs) poi / poa evaluation on a plate will mess your head in.... just my opinion of course

 

[squimp]

I acquired a 28 bore a few months ago and because I will be shooting very light loads (up to 21g) I tried comparative testing of various cartridges on a home made pattern plate. Part of the reason for this exercise was the dearth of concrete info on what 28 bore barrels/loads actually do down range. Indeed much of the US information (28 gauge is popular there) appears contradictory. Some suggest very open chokes and others very tight.....

I didn't go as far as counting the individual pellet marks,  but did a fairly careful spread and  'evenness' evaluation of the pattern from each load with multiple shots. 

What I learned was that different cartridges threw very different patterns thru' the same choke (Teague multi). Interestingly the widest pattern came from a plas wad shell, 3 different fibre equivalents produced markedly tighter patterns. 

In terms of choke constriction, the results were pretty predictable. Very tight chokes were a disaster at anything less than 30m and my quarter choke (equivalent)  was fine out to a sensible distance. 

However I take IPS's point that actually shooting the gun/load combination is where it really matters. I shot the gun at clays  before I had it multichoked and couldn't hit anything close, but it was great at 40m ! The reason for that was the factory fitted super full choke!!!    

 

[Doctor Lecter]

to quote a ex world champion coach       when you shoot a competition  and call for a report or sim pair of pattern plates  , until that happens  test your pattern on a dtl target  , it will tell you all you need to know !   :clapping:  

 

[Will Hewland]

When I started I did sod about trying to set up my adjustable comb on a pattern plate. I got it "spot on" and didn`t realise that it would hurt my clay shooting for months as it was way too low for real use. As IPS says, shoot a going away clay if you want to prove you can shoot where you're looking.

I now only pattern to suss out what a new cartridge behaves like and I keep it really simple. I shoot a sheet of cardboard at 15 yards. I gently move the gun upwards and just before I reach the centre of it, I pull the trigger. This centres the pattern on the cardboard for me.

I am merely comparing different cartridges and for this I reckon you can tell all you need at 15 yards. (A trap shooter would do better to mimic the exact distance they use every time). As a sporting shooter I will be using any cartridge over a wide range of distances, but patterning nearer or further just does what you would expect, its a cone. A good even pattern at 15 yards remains good at 30 yards (just wider of course) and a crappy one gets crappier. I also don't do multiple cartridges to prove the point as there tends to be no big difference I find. If there were, then I would not use that cartridge! 

So basically I prove that a cartridge can distribute its pellets evenly and is not ridiculously tight or ridiculously dispersed. Hopefully that cartridge is reasonably priced, available locally and has moderate recoil. Then I'm happy and can just think about the clays.

 

[Freddypip]

There is useful chart from Briley which covers targets, distances and recommended chokes. It is surprising that only clays edge on over 35/40 yards really need more than MOD (1/2) choke.

Many years ago, Mike Yardley did a review of choke sand found the standard Beretta mobil 1/4 quite reliable and consistent.

Putting these points together - 1/4 and 1/2 seem good though I'm 3/8 and 5/8.

On the pattern plate it's pointless repeating choke and cartridge combos - you could be there for years & forget what you were looking for. I would use a 1/4 at 30 yards and mount & shoot 2 or 3 (perhaps 4) times into the same board and look at the spread. If looks OK then walk away. Shooting once always leaves gaps which then raises questions . . . even a tight choke has gaps. As DL has pointed out, shooting a going away clay, standard teal (at the top of its rise) or skeet layout,  will tell you more about your mount and gun & fit that shooting at a fixed target.

I understand that tight chokes with some cartridges can cause the pattern to blow - this is more noticeable with a short choke where the reduction in construction is quite severe. Modern chokes tend to be longer. I am not a scientist however !!

 

[Westward]

If you're self isolating and can't face yet another jigsaw puzzle or even worse, daytime TV, here's an interesting read about patterning: https://www.shootingtimes.com/editorial/longgun_reviews_st_headintheclouds_201002/99884

 

[Geordieboy]

My 725 3/4 choke measures 3/8 and gives me the best pattern at 80%.

L.Full measures a true 3/4 and gives 82% density (I think that's right without counting the patterns again )

My Perazzi Teagues are true measurements to bore size and most dense is 3/4 choke at 85%.

Theres more going on in the barrels earlier on methinks than just your chokes at the end.

 

[squimp]

My 725 3/4 choke measures 3/8 and gives me the best pattern at 80%.

L.Full measures a true 3/4 and gives 82% density (I think that's right without counting the patterns again )

My Perazzi Teagues are true measurements to bore size and most dense is 3/4 choke at 85%.

Theres more going on in the barrels earlier on methinks than just your chokes at the end.

When you say 'true' choke measurements I assume you mean:

3/8 is 15 thou constriction and 3/4 is 30 thou  as compared to the nominal bore etc etc ??