Testing pistol loads/rests?

[jmorris]

How would you guys feel about something like this?

I have not had best results with semiauto pistols with something like that.

It really depends on a lot of variables, “pistol”, even though somewhat specific still covers a lot of different firearms and what works best for one might not be ideal for another.



We (being the largest variable) also expect different things out of our “pistols”. So there really isn’t a right/wrong method/expectation. Why I suggested testing a number of different methods to see what works best for you with a given firearm.

As for repeatability of POA and sights, the best optic will always beat the best iron. If that were not fact, benchrest shooters wouldn’t use optics because they would be inferior. No game exists that precludes the use of “irons” because they would be an advantage.

 

[LiveLife]

As for repeatability of POA and sights, the best optic will always beat the best iron. If that were not fact, benchrest shooters wouldn’t use optics because they would be inferior.

+1. My current method of accuracy testing is using pistol caliber carbine on bipod with DIY adjustable rear bag below A2 fixed stock.

Repeatability is such that I can detect accuracy trend of .2 gr change in powder charge I would likely never be able to detect using pistol at 25 yards and possibly miss out on an accuracy node.

Below is 25 yard groups with RMR 115 gr FMJ loaded at 1.130" and shot from 17" Just Right carbine using 6-18x50mm and bipod. If shot with pistol using iron sights, I may have different results depending on my input on trigger/pistol grip - https://www.thehighroad.org/index.p...-and-vectan-ba-9-5-ba-9.817796/#post-10508215

IMR Target 4.5-4.6 gr (Left), 4.2-4.3 gr (Center) and 4.0-4.1 gr (Right).

Or be able to tell the subtleties between bullets when other reloading factors are equal. Below is .356" sized Zero 115 gr FMJ compared to .3555" sized RMR 115 gr FMJ. I think optics definitely have advantage over pistol iron sights - https://www.thehighroad.org/index.p...anging-bullets-thoughts.818764/#post-10502502

And here's 25 yard groups with adjustable stock with addition of .355" sized HAP. Does a small reloading variable such as more gas leak from .355" vs .3555"/.356" bullet sizing matter? I think so as shown by the groups. And can you see what appears to be vertical stringing? I think I can.

 

[jmorris]

That’s what I was trying to say in #14, it’s not as easy to do something like this with most pistols, where the best way to see if one load is more accurate than another is to get further away from the target so the groups can become more than just a hole.

 

[LiveLife]

Good point.

I have done a lot of comparative accuracy testing with scoped carbines at 25 yards and what I realized is while I can still see shooter input on groups, I can start to separate out other reloading variables like powder charge variance that I may not have been able to detect with pistol using iron sights at 10-15 yards.

This link shows 24 loads (and growing) that have been tested so far in PCC - https://www.thehighroad.org/index.p...n-9mm-40s-w-45acp.799231/page-4#post-10338994

Since then, in tune with your recommendation for 10 shot groups instead of 5, I have worked to isolate additional reloading variables for accuracy testing such as headstamp case wall thickness variance and bullet setback.

 

[egd]

BDS, I have a question. I've always read/heard that every gun is different and you have to find the right load combo that your gun likes best. If you are using a pcc to test accuracy wouldn't that be just testing for THAT gun? It wouldn't necessarily be the same in a pistol, or even another pcc for that matter would it?
Granted it would be close I'd think, but if you're talking of changing powder loads by only a tenth or two of a grain, wouldn't you still have to test in the gun you want the load for? Therefore back to square one, so to speak.

 

[LiveLife]

You are absolutely correct.

How a particular load performs in a pistol with tighter groove diameter, chamber and shorter leade may perform differently for another pistol or carbine with larger groove diameter, chamber and longer leade. With that said, there are certain loads that seem to shoot well regardless of the pistol/barrel. One load is 45ACP 200 gr SWC with 4.8-5.0 gr of W231/HP-38. Most people report this load to be very accurate in their pistols. Another load I use is 45ACP 200 gr SWC with 4.0 gr of Red Dot/Promo and with softer 12 BHN MBC Bullseye #1 200 gr SWC, it is accurate in various 1911s, M&P45 and even in my PT145 with oversized barrel.

While we can gauge the accuracy of any load with group size, for comparison with other powders, I conduct my accuracy tests along with known reference loads. For 9mm, it is 115 gr FMJ with 4.8 gr W231/HP-38 and for 45ACP, it is 200 gr SWC with 4.8-5.0 gr W231/HP-38. So if a new load produces smaller/larger groups than reference load, regardless of firearm used, I can "gauge" how accurate the load is comparatively. Also, if I am having a "bad range day" where I can't seem to group anything, shooting known reference load will help me determine if it's me or the new load.

When I tested Vectan Ba9.5 (Powder I have never used before), I first shot a reference group with W231/HP-38 and then shot the powder work up. For the picture of comparison shot group, I did not include the 3.6 gr Vectan Ba9.5 load because grouping was very poor - https://www.thehighroad.org/index.p...ectan-ba-9-5-ba-9.817796/page-2#post-10519646

So without the W231/HP-38 reference load, I would not know how accurate the Vectan 4.1 gr load was in comparison to other powders but since I shot with my reference load, I could say the Vectan load was comparable to reference load in accuracy.

25 yard 10 shot groups with RMR 115 gr FMJ at 1.130" with 4.8 gr W231/HP-38 (Left), 3.9 gr Vectan Ba9.5 (Center) and 4.1 gr Ba9.5 (Right)

Here are 25 yard IMR Target groups - RMR 115 gr FMJ at 1.130" with IMR Target 4.5-4.6 gr (Left), 4.2-4.3 gr (Center) and 4.0-4.1 gr (Right). So in comparison to my reference load, 4.2-4.3 gr IMR Target load was comparable.

Keep in mind that most powders will produce smaller groups with higher powder charges. But IMR Target produced smaller group with mid range load data. This is good example why we need to conduct full powder work up as accuracy node can sometimes occur not near the top.

For RMR 100 gr Hardcore Match RN (rated to 1500 fps) testing, I used 5.5 gr of W231/HP-38 loaded to 1.050" OAL (Hodgdon max charge) as reference to compare with Promo 4.5-4.7 gr (extrapolated from 2004 Alliant load data for Red Dot for 95 gr FMJ at 1.055" with 5.3 gr max charge). Had I just shot the Promo load, I would not have known whether the group was good or bad but since I had the HP-38 load to compare, I would deem the Promo group to be comparable to HP-38 - https://www.thehighroad.org/index.p...n-9mm-40s-w-45acp.799231/page-3#post-10245856

 

[Ru4real]

The secret to shooting good groups with a recoiling handgun is controlling recoil consistently for each shot. Once mastered, your point of impact resting will be different than off-hand. Because of this fact, once a load is dialed in to my gun I shoot with a lighter grip from a rest if I choose to shoot from a rest.

To shoot the best groups from a front sand bag rest, grip firmly both hands with heavy down pressure into the bag. Do what is necessary to keep barrel and gun still until bullet clears the bore.View attachment 783463

 

[thomas15]

At 4.3 it wouldn't even hit the 6x6 paper i was like WTH!! BE86 shot 5 shots within say 3x3.

I have been trying to come up with a load that uses 38 spl cases trimmed to approx. 38 long colt length. I picked a arbitrary length that is longer than the long colt and started using my favorite powder titegroup. I have been at it for a few weeks and my first attempts were not good at all, I could hit a 6x6 paper but the hits could be anywhere on that paper. This at about 30 feet. I do not have any load data so I've had to sort of make up things as I went along.

Long story but I have found something that works fairly well, it uses a totally different bullet, different dies and a different powder from where I started. My ladder loads indicate that the difference between loads that are .2 grains different makes a big difference in the way the ammo shoots. While I'm not trying for a particular power factor at this time I want something better than a bunny fart.

The problem is of course you need to make small changes then test as a complete overhaul will not tell you what is wrong. This requires patience which I have except I'm under pressure as the weather here has not been good and I need a viable load in about another week.

 

[LiveLife]

BDS, I have a question ... If you are using a pcc to test accuracy wouldn't that be just testing for THAT gun? It wouldn't necessarily be the same in a pistol, or even another pcc for that matter would it?

Granted it would be close I'd think, but if you're talking of changing powder loads by only a tenth or two of a grain, wouldn't you still have to test in the gun you want the load for? Therefore back to square one, so to speak.

In addition to post #31 where I addressed the use of reference load to verify accuracy, consider this.

What produces accuracy?

To me, accuracy results from:

• Reloading variables that produce more consistent chamber pressures which then produce
• More consistent muzzle velocities which result in
• Lower SD numbers
• Smaller groups on target

While there are factors that vary from firearms:

• Chamber dimension for more/less gas leakage as case mouth seals with chamber walls
• Bullet jump to start of rifling (leade/free bore) to build pressure vs gas leakage
• Groove diameter vs bullet diameter
• Rifling type - Land/groove vs polygonal and 6 riflings vs 5 riflings (M&P)
• Barrel lock/time vs tolerance for repeatability
• Barrel length
• Trigger, etc.

So if we start with a verified accurate load which has optimal shortest OAL for greatest neck tension and highest powder charge that produced efficient powder burn with least amount of taper crimp for fastest sealing with chamber walls, this load should produce the smallest groups regardless which firearm it was shot in.

Yes, there will be varying levels of accuracy produced from firearm to firearm but I can't imagine a less "accurate" load producing greater accuracy just because it was fired in a different firearm. Perhaps we can myth bust this notion in a future thread.

And what about gas leakage vs neck tension?

I have wondered about that for years as general notion was closer you were to start of rifling to reduce gas leakage would translate to smaller groups. Well, I found that is not the case for 9mm and even for rifle cartridges where bullet jump and skip to rifling vs initial pressure build have benefits.

When I myth busted this in 9mm carbine with longer leade, I thought perhaps longer OAL, which reduce gas leakage due to faster bullet to start of rifling time, would produce greater accuracy. As shown in the groups below with RMR 115 gr FMJ and 4.2-4.3 gr of IMR Target, longer 1.155" rounds on the left produced larger group than shorter 1.130" rounds - https://www.thehighroad.org/index.p...g-oal-col-long-vs-short.819257/#post-10511700

Since my latest Lone Wolf barrel with short leade requires 1.110" OAL, perhaps I will do a comparison test with 1.130" and see which load will produce smaller groups. My guess is 1.110" load. And if that's the case, 1.110" OAL distance to lands becomes less relevant and we are talking initial chamber pressure build and faster case mouth sealing with chamber wall overshadowing other factors. And this "optimized for accuracy" load should produce smallest shot groups regardless of firearm it is fired in, at least in my theory, and I am sure I will be doing some more range testing to verify this.

25 yard 10 shot groups with 4.2-4.3 gr IMR Target and RMR 115 gr FMJ 1.155" (Left) and 1.130" (Right)

 

[Iroquois]

I've used this old Hoppes rest for years and it has served me well.

 

[jmorris]

The author also notes that, "Even the Army Marksmanship Unit recognizes that, “Extremely uniform velocities alone are ‘not’ a reliable predictor of accuracy!”"

If we concede that the person firing the firearm is the main variable, this is pretty obvious.

 

[LiveLife]

And isn't that why we perform accuracy testing as "holes on target" ultimately determines accuracy of loads, firearms and even shooters.

When I was going through basic rifle training in the Army, my Sergeant saw I was pulling my shots to the right of POA. He went over trigger control but when he realized my groups were consistently tight to the right of POA, he said as long as I was consistent in pulling my shots, I simply needed to adjust my sights to compensate.

We can discuss all we want about what should produce accuracy but as rcmodel often posted "Shoot 'em lizbeth", we should let the holes on target dictate what ultimately produces accuracy. Many times, I had my notion of what powder, charge or OAL should produce best accuracy but when the holes on target formed different groups than what I expected, in the end I had to concede and go by the group size.

Not too long ago, jmorris challenged my use of 5 shot groups as lacking information and suggested using 10 shot groups instead and illustrated that out of 10 shot groups, there could have been many 5 shot groups that only told "part" of the story. Now, I only use 10 shot groups to determine accuracy of loads being developed.

Then Bart B. challenged my practice of eliminating "flyers" from my groups and suggested I count every shot, including flyers to determine my groups. I objected at first, as I felt flyers were caused by factors beyond my control, such as from using mixed range brass. After extensive carbine testing (over 30 loads and counting), I began to realize flyers may be caused by me as 10 shot groups after 10 shot groups illustrated less flyers when I switched to fixed stock and more stable shooting platform (prone shooting with bipod and fixed stock instead of unstable table shooting with bipod and collapsible stock).

I have been working through eliminating various reloading and shooting variables and have learned a lot and threw out several notions I have held like longer vs shorter OAL.

In the end, holes on target do not lie but speak the truth. If we interpret the holes truthfully, they will help us identify reloading and shooting factors we can improve to produce more accurate loads.

Of course, this is based on my personal experience and opinion only. YMMV.

 

[jmorris]

we should let the holes on target dictate what ultimately produces accuracy.

That’s it, as long as you can discern a difference between changes, if you cannot, they don’t really matter much.

If your shooting 3” groups at 15 feet, it’s likely not your ammo. At that distance you couldn’t tell 100 fps difference in velocity, ES and SD are just not a significant factor that close. Ballistic tables can tell you all you need to know about that.

Yes, we should always strive for perfection but it wouldn’t be the best, especially for close range pistol load to focus solely on velocity, except to ensure that you always make powerfactor for gun games you might be playing.

 

[rfwobbly]

As far as human factors are concerned... what you aim at makes a huge difference. The human eye really can't pick up cross hairs and all these multi-color graphic shapes available on newer targets without using a scope. For open sights there's nothing like a solid back circle. The eye simply needs something small, with high contrast. For open sights on pistol there's nothing like a 2" black dot at 10 yards.

 

[nevadabob]

I made one like this:

 

[graying wolf]

44 mag. different bullets and different loads.
All shot at 25 yards using two ratty old sand bags.

 

[RAT807]

I use a Caldwell Rock rest and either a rabbit ear bag or similar small bag for the grip to rest on. I test loads at 25 yards. To shoot all of your rounds perfectly, without any errors, is well, impossible. Grip pressure will change, front post will drift to one side or both if you start to shake and then there's that urge to snatch the trigger instead of applying smooth pressure all the way back. For these reasons I shoot in 5 shot strings.

You will need to figure out how to hold your sights in the same location for all shots and note any shots that break, off your point of aim. I have different targets for different uses but most targets have a white or light colored background. I can not be precise when holding black sights on a black bullseye. I need contrast, white background, black sights and an orange dot are my tools of choice. My sight picture has the front post at 6 o'clock on the orange dot. I can see clearly, white on both sides of the front post and the dot on top of the front post. This is easily repeatable but you also need to be aware of the other 6 shooting fundamentals to have excellent results.