Accuracy-X Upgrade to my Springfield MilSpec

A couple of folks have asked me if the Accuracy-X upgrade to my Springfield Armory Mil-Spec .45 was worth the $1700 cost. I finally made time to find out, using my new Ransom Rest. Please be mindful that this was my first try at the Ransom Rest. It was an enjoyable experience. 
  I tried three different loads in three different pistols. One Zero 200gr. LSWC, one Oregon Trail 200gr. LSCW and one Zero 185gr. JHP.
  The Springfield lower is factory stock, with the Accuracy-X complete upper. It came with adjustable rear sights, and a Leupold red dot base.
  The other two test guns were my Colt Gold Cup NM, stock except for a drop-in Briley spherical bushing, and a Colt Gold Cup NM with a KKM barrel and drop-in Briley spherical bushing. The KKM was my first attempt at fitting a barrel.
  One interesting item noticed in this test, was the deviation from the group whenever I changed magazines. Each time a mag was changed resulted in a flyer from the group.
  I look forward to using the Ransom Rest for testing bushings and barrels going forward.
As for the Accuracy-X test result, let me know what you think

2.8 BE is that right????

I read 3.8 BE.

rich.tullo wrote:2.8 BE is that right????

Rich,
3.8gr Bullseye is correct. The 200gr Oregon Trail and Zero don’t fly sideways using the extra powder.
I do use 2.8 with 148gr HBWC in my model 52.

Try using the same mag on the second string. And try 4.0 BE and a heavier recoil spring to see if the group tightens up. That might get you under 2 inches.

If you are not already doing this, shoot 4 out of the magazine, then with the 5th loaded in the barrel, reload and/or insert a magazine with the remaining 5.
Phil

See above... never let the pistol go empty between mag changes.. also many times it's worth throwing the first round  off the target..

As noted above, RRs can be a little crazy with the first round out of a semi-auto. It's because the first round is 'hand cycled' whereas the rest are fired cycled. This can affect lockup with some guns. The fix is to shoot the first round from a magazine off target so it is not included in the group. This might also include the first round after a mag change even if the gun already has a round in the chamber, because jostling the gun around during the mag change might have a slight effect on the slide/barrel/frame position in even the apparently tightest gun.  Yes, it's a pain in the butt, and it requires more ammo, but you want the gun and all its parts in the same position for every shot in your group.  I've seen some pretty wild first shots in my RR tests, like inches away from the rest of the group.

Also, for more rigorous testing, shoot more than 10 shots in your group. 

You might find these articles of interest;

https://www.ssusa.org/content/accuracy-testing-shortcomings-of-the-five-shot-group/

https://www.ssusa.org/content/accuracy-testing-how-many-shots-in-the-group/

OK. Very informative post. But I guess that it illustrates, for most of us mere mortals, why RR testing becomes rather "academic".

Now, I'm gonna sound like a SNOB, sorry. But, when you know that you've got a good gun and reliable ammo, everything else had to "flow";

A 2" or even 3" gun will shoot better than you!

Ya just gotta get up there and shoot!

https://www.ssusa.org/content/accuracy-testing-shortcomings-of-the-five-shot-group/ wrote:
https://www.ssusa.org/content/accuracy-testing-how-many-shots-in-the-group/

I'm not sure these get it right either, statistically.  Group size, as measured by distance between the two shots furthest from group center, tells more about the tails of the distribution than the distribution itself.  IMO a better measure would be the mean distance of a series of many POI's from the group center.  A more accurate setup (gun, bullet, load, etc) would have lower standard deviation of mean distance from center than a less accurate setup.

Analogous to these normal distributions (of a different parameter), the blue curve would be that of a more accurate setup, the yellow less accurate

https://cdn.scribbr.com/wp-content/uploads/2020/10/normal-distributions-with-different-sds.png

True, the yellow distribution would have more "flyers" than the blue, but you really need many POIs to determine the expected behavior (accuracy over many shots).  It is risky to conclude much from 5 shot groups, or different behavior of (say) first and last rounds in the mag, different mags, etc.

To further, Roy's comment, this is bullseye pistol not bench rest pistol. Testing is important, but it is best to test in the most match relevant matter. 10 shot groups make up one long line target, 30 makes up the composite for the 900 match, note you don't need all the shots on the same repair center. If you ever are in the position for the slide to lock back during SF, it also is a good idea to know what that result is from the rest, same goes with different magazines. It also only makes sense to test ammo that you would shoot at a match. If you are going to only shoot handloads, why waste time (and money) with factory ammo? 

Testing is an important part of a shooting program, but the goal would be to get the most useful data with the least amount of time and effort such that you don't take too much away from developing the more critical part of the match system, the shooter.

That makes my head hurt
Phil

S148 wrote:As noted above, RRs can be a little crazy with the first round out of a semi-auto. It's because the first round is 'hand cycled' whereas the rest are fired cycled. This can affect lockup with some guns. The fix is to shoot the first round from a magazine off target so it is not included in the group. This might also include the first round after a mag change even if the gun already has a round in the chamber, because jostling the gun around during the mag change might have a slight effect on the slide/barrel/frame position in even the apparently tightest gun.  Yes, it's a pain in the butt, and it requires more ammo, but you want the gun and all its parts in the same position for every shot in your group.  I've seen some pretty wild first shots in my RR tests, like inches away from the rest of the group.

Also, for more rigorous testing, shoot more than 10 shots in your group. 

You might find these articles of interest;

https://www.ssusa.org/content/accuracy-testing-shortcomings-of-the-five-shot-group/

https://www.ssusa.org/content/accuracy-testing-how-many-shots-in-the-group/

It is interesting to hear about the nuances of using a ransom rest. I used one at my club and it definitely took some finesse to get it settled in the grip clamps and point at the center of the target repeatedly. 

Seems like there are a lot of -isms and caveats. At some point we will be artificially creating a group or accuracy potential that can not be replicated under match conditions because of various limitations such as not being able to fire the first shot off target.

In my opinion and experience, the first shot flyer, or any shot flyer is part of, and should be included in the group test. To discount it only proves a false potential. It is what it is, and I hate that phrase.

In SF one "may" have one manually cycled chamber round whether it be load 5, shoot 4, load 5 more, or load 6, shoot 5, load 5 more. Either should eliminate two manually cycled chamber rounds. I don't think it matters if the manually cycled round is while on RR, bench and sandbags or off hand, If a manually cycled round prints to a different POI, then it does. I have found some very good shooting guns do this, whereas some others do not. Again, if they print "out" of the group of other shots, they are still part of the group.

Some nonscientific thoughts as to why it may happen, other than the obvious that the lock up varies.

Consider:
Trying to determine if the flyer changes whether it is released from slide lock via the slide lock latch vs pulling it back then let it chamber from that position, vs having the slide forward (battery) on an empty chamber then insert loaded mag, then pull slide bag all the way and release it vs using a separate mag with only one or two rounds in it. Use that mag to chamber the first round, then replace that mag with a 4 round mag. The later can be used in TF and RF since you are not violating the "with 5 rounds load" command. The later could identify if the greater resistance on the slide traveling forward, reduces the necessary slide speed/inertia to more closely resemble the slide speed of the automated chamber when the gun is firing. If the later holds true in tests, then possibly reducing some of the magazine spring tension may be worth a consideration as well.

My .015 worth.

Interesting information. The main reason I have the Ransom Rest is to test the handguns that I install barrels, bushings, etc. into. So far, the biggest surprise has been group sizes with various bushings. 
I also will get to see which is more accurate, my Python or my K-14
Other than such fun stuff, load testing will provide me with valuable data, so that I don’t waste time and components.
Thanks to everyone for the comments and suggestions.

There is a growing consensus that the majority of guns in any specific caliber, pistol or rifle, will shoot acceptably accurate with some common loads.  In other words, your pistol or rifle in a given chambering load will very likely shoot acceptably with the ammunition somebody else found to shoot accurately in his particular gun.  It might not be the “best” but it should shoot acceptably.  So testing is fine, but don’t let it consume your efforts that are better spent elsewhere,

PMcfall wrote:If you are not already doing this, shoot 4 out of the magazine, then with the 5th loaded in the barrel, reload and/or insert a magazine with the remaining 5.
Phil

OK, I've never heard of doing this, why do this?

KB2MBC wrote:

PMcfall wrote:If you are not already doing this, shoot 4 out of the magazine, then with the 5th loaded in the barrel, reload and/or insert a magazine with the remaining 5.
Phil

OK, I've never heard of doing this, why do this?

Greetings,

This is done so that the gun fires and cycles the slide by itself.

Cheers,

Dave

Interesting all.

inthebeech wrote:Also, are ther not ten round magazines?

Test with what you plan on running. If you shoot 10 round mags for slow, test with a 10 round mag. 

Again if you are not going to do something in a match, probably not worth the effort of testing. 

Ideally in a good setup the fliers attributed to first shot, last shot, mag change, ect. are negligible. The 3.36" 10 ring is a lot of room for 10 shots.