Which parameters affect accuracy in pistols?

[Pond, James Pond]

It occurred to me that I have spent all sorts of time on trying to find accurate loads for my rifle, yet I can load a batch of test charges for my revolvers, shoot them over a chrono and pick the one that has about the velocity I want and shows no over pressure signs.

Admittedly, my pistol rounds rarely if ever get aimed beyond 25m, but I started thinking about how I might improve the potential for accuracy in my pistols rounds.

So we have OAL: might be governed by a cannelure, or chamber length, but I suppose there is often some room for variation.

Crimp: this seems sort of set, in that we use it to keep the bullet in place, or help build pressure for a good burn. I certainly need some but can't go mad either: seems this lacks much room for adjustment and so may not help much.

Powder charge: the faster, the flatter shooting I suppose but beyond that, I don't know how it could greatly affect accuracy.

Powder choice: again, I don't know to what degree another powder helps accuracy in a pistol cartridge.

So, tell me where I'm missing potential for improvement.
What are the variables I can tweek once I have a bullet traveling at a speed I want from cases that will keep the bullet in place until fired?

Question Edit after some responses:

So I write this after some responses as I suppose adjustments that are applicable to my situation are more useful, even though all knowledge is handy.

I was asking mostly in the context of my revolver reloading.
Powder choice for me is limited, but if it is V.V., I can get it. In .44 I could get fast N320/310, medium N350 and slow N110, amongst others.

I load with N110, but have used N350.

Crimp for me is quite set as I have the Lee FCD and my first concern is keep that bullet stationary under recoil. I have only once used crimp to try and improve ignition.

OAL, I can go shorter or longer, but not too much with my smooth-walled plated bullets.

Bullet choice: I have a small selection in .44 cal. Plated and some jacketed.

So here is my revised question:
Which parameters can I adjust, given my set-up, to affect accuracy in my revolvers?

[serf 'rett]

...once I have a bullet traveling at a speed I want from cases that will keep the bullet in place until fired?

How would you know that the particular speed you pick is the best for your particular primer/powder/bullet/brass/OAL combination? Perhaps a different velocity would give you better groups.

I don't own a chrono (yet) so I normally pick a bullet/primer/case/OAL and then load a series of charge weights, in 0.2 grain steps. Testing the series, at a set distance using sandbags on a bench, will yield some groups, which can be used for further testing.

What are the variables I can tweek

Can tweek almost any that you have listed, but some would likely have little effect.

When I get a particular bullet, I will often develop loads with fast, medium and slow powders to see which combination gives the best groups.

Powder charge: the faster, the flatter shooting

Faster is not always the most accurate.

[SpringOWeiler]

As somebody with the same testing process with you. I did the unspeakable!
Put away the chrony.
To put it metaphorically chronys can basically turn us into dogs chasing their own tails. I made a thread about 44's with sub reduced loads and received (in my opinion) heavy flak from those who think a gun HAS to shoot X bullet weight at X velocity.
My results were everything I wanted, and accuracy was exceptional.

Just for thought
Reloaders think of a 1,000,000 reasons why their gun won't shoot some bullet well, and the individual marksmanship skills of the shooter are still generally not listed as a possibility.
I loaded up about 500 240gr XTP's at max with H110/296/2400. You know the hottest of the hottest and couldn't shoot good groups with them after 3 shoots. I could hit a 12" plate at 25yards everytime because i subconsciously developed a flinch to accommodate for the power level. I noticed it by loading 3 and spinning the cylinder so sometimes I would strike an empty chamber. I personally found it to be unacceptable and decided to return too the basics and make lower powered rounds and practice with those. Now I load 6 but mix in a full powered 44 and spin the cylinder so I don't know when it comes up.
My EDC gun is a glock 20 10mm and I used to do the same thing, my biggest reloading mistake was loading 600 rounds with large rifle primers by accident. End result was 1-7 strikes to make the round go off. Every time they went off was a surprise and instead of being sullen about my mistake I took advantage of it and put a substantial effort into managing my flinch. It paid off very well for my marksmanship skills.

[1stmar]

Crimp is anything but set. It is variable and has a big impact on accuracy. Roll crimp, taper crimp, collet crimp .. Heavy crimp, light crimp. You get the idea. If you over crimp it will be sufficient to hold the bullet during recoil yet you may deform the bullet.

[bfoosh006]

I realize this answer is not in the spirit of this forum...but...IMHO , buy a high quality replacement barrel if you can.

Every pistol I own I have bought better barrels for. My Beretta 92 was the most improved.

And it made more difference then all my experimenting with reloads.

[DaleA]

My experience was I got into a league with some shooters and most used .45 ACP 1911 guns and 185 or 200 grain lead swc with Bullseye powder and I just kind of followed along.

I tried a variety of stuff since then and have found cleaner buring powders and powders that will give me greater velocity when I want to do something besides paper punching but unless practically everybody agrees that x powder with y bullets is just the best thing going I'm probably never going to get off my 200 grain lead swc and Bullseye combination.

Do you have any league competition shooting over there?

Here in the US I've almost always found shooters to be pretty free with their advice about what is working best for them and it usually was something that was available locally too although THAT'S certainly changed the last year or so.

For me OAL and crimp was what I found would function in my .45 1911 (I use the 'plonk' test and a taper crimp) and I've never varied those to try get more accuracy-for me they are a 'given'. I guess (again for me) powder would be the biggest consideration in loading for accuracy.

[Pond, James Pond]

I should have known!

I posted a question on TFL and I got a stack of answers!!

OK, so I have edited my OP to get more focussed responses. They have all been useful to read about, but in my case, they are not all workable.

[1stmar]

Given your limitations, I would expect bullet type/variation to be the first thing to look at it. Recognizing you have few bullet options what are they? I would start there and then work with your limited powder options. Bullet selection, powder selection, charge selection, primer selection, bullet depth selection. That would be the order I worked in. Assumes all brass is same headstamp. Brass would be another variable but for pistol I doubt it will make much difference as long as you are using all the same brand. Is this just a target load ?

[Pond, James Pond]

Bullet selection, powder selection, charge selection, primer selection,

Bullets:
Plated truncated cone bullets designed for sports/target shooting: any thing rom 180gr to 300gr.
Jacketed or JSP from PRVI: 240gr
Of anything from Midway Germany, but I won't go down that route again because of the $$$$$.
I have used 200gr and 300gr plated bullets. I'd like to their 240gr SWCs too.
Jacketed I have tried too.
I bought a one-off batch of cast bullets from Midway for a woods load. 275gr.
The plated bullets are my preference because they are cheaper by almost 50%!!!

Powder:
As I said, the VV range is at my disposal. One stockist also have Hodgsons, but not a big selection for revolvers. Only Universal, so far.
Either way, they are expensive (€90-110 per kg) so I can't afford to buy and try.... only buy and use, whether I like it much or not!!

Primers:
Fiocchi large pistol or CCI large pistol (although 90% of the time it is Fiochhi. I have seen Winchester too, but only for small rifles.

For brass, I have used my once fired S&B brass as well as Starline ordered online. I could also get Magtech.

So that is why I have predominantly only really considered OAL, powder charge variations and a very small range of crimp as options.

Am I over looking anything that could help amongst those?

[1stmar]

Generally speaking swc should give you the best accuracy (depending on distance). I would start there. After swc I'd probably be looking at hollow points. I still think that bullet selection will have the greatest impact on accuracy assuming an appropriate powder. Lead bullets are generally oversized a bit more then copper. You can probably get sufficient accuracy from vv powders assuming it matches your bullet weight. Starling brass is very good (or at least it used to be) so you should be ok.

[Misssissippi Dave]

Just as a general things I do to get accurate loads. I try to match the weight of bullet to the powder. Lighter bullets I use a faster powder and heavier bullets I use a slower powder. This generally produces combinations I can tweak easier. The twist rate of the barrel might also determine if heavier or lighter bullets will give you better accuracy as well. The twist rate seems to make a greater difference with rifle ammo but it also affects pistol ammo.

The other items are the weights of the bullets. I try to get bullets that weight pretty much the same for accurate ammo. I look for .1 grains difference between the heaviest and lightest of the ones I am using. For general ammo I go with manufactures that normally give pretty consistent bullets. I have seen some bullets that varied 3.0 grains plus or minus what the box said and that means 6 grains from top to bottom. Something varying that much might be good enough to shoot frogs with. I find hollow point bullets seem to stay more accurate at longer distances. I believe it has to do with where the center of gravity is to stay stable. Placing the same amount of powder in each case and keeping the OAL the same is also important. All these things have one thing in common. Loading the same round every time instead of close enough. You do have to play around a bit to find just how much powder is needed to match your gun. Finding the bullet weight that matches the barrel twist rate is also a factor. I'm sure crimp is also a factor but I have not found it to be as much of one as the bullet weight or burn rate of the powder. Hollow point bullets seem to help only when you are shooting beyond 25 meters. In handgun calibers, distances of 50 meters and more seems to improve things with hp bullets. It might help under 25 meters but I have not seen enough difference to say it does.

The majority of the pistol shooters I have know probably couldn't tell the difference between a very accurate load and one that is just a bit better than the cheapest factory ammo you can buy. If you are not able to shoot a handgun well to start with, will firing match grade ammo improve things? Maybe but probably not.

[Mike / Tx]

Realizing as we have conversed before in PM's, your powder is limited to what you can get as well as your bullets. I'll try and keep that into consideration as I go along.

Personally when I set out to develop my "accuracy" loads I usually pick a bullet weight which is in the middle of the road for a caliber. Not to say that the lighter or even heavier cannot shoot accurately, but if I have a mid weight accuracy load I can usually use that as a comparrison to work with for the other two.

I try and choose the powders in a similar manner. If I know I am looking for something to hunt with I look at the slower powders first, rather than the faster ones you might choose for target loads. If I am hunting in most cases I want all I can get in one shot as the recoil isn't as much of a factor. In target shooting the recoil will wear on you after several dozen rounds and isn't good for consistent groups. Usually the faster powders have less recoil to a point than the slower ones designed for the magnum type loads.

I have found the biggest gains to loading accurate revolver rounds to be trim length, case tension, and crimp. Either of these will effect the pressure and or the accuracy of the load to some extent, sometimes one being more than the others. That said if your looking for top end accuracy, then they all need to be as close to the next as possible. I am sure you might have seen this, but it is a comparrison of the exact same load, side by side, with the only difference being the adjustment of the crimp,


The sticker is a 2" dot and the range was 40yds, both shot with just the forearms rested on a towel across a small table. My friend was having issues with this particular load in his 41 magnum, and was telling me I was crazy that it shot good. I along with several others whom I recommended the same load to have been using it for years with great accuracy, so I knew something was amok with his loads. When we stopped by I took him to task on his crimp, which looked like he was trying to pinch the lips off the cases.

I usually start off with only enough to actually see that the lip has rolled into the cannalure. Then I will load up a couple or three increasing the charge weight of each by around 2/10 of a grain from the start to the max load. It usually doesn't take much effort to see where one load will group a bit better than the others at 25yds. During this time I will shoot them one at a time.

From there I take the best load(s), and will load up 10 or 20 of them depending on just how well they did. I will do, as you have done where you load 5, shoot them in order and check the last round measurement each time for growth. If I find anymore than .002" I adjust the crimp to have only enough needed to hold that same bullet in place through two cylinders full. Usually if they haven't moved in that span they aren't going to.

I have found that this really doesn't effect the group size much going about it this way, but if you start about it the other way having the crimp extremely tight to begin with, your groups might be all over the place so you don't know if you have had a good load or not. I have also found this to apply when using a taper crimp as well. With my target only loads, I sometimes seat them out past the cannalure so that they will still fit the cylinders, but have no groove to crimp into. I am also usually using faster powders like Bullseye and Unique, or in your case Universal, and my only aim is putting one round after the other though the same hole, not so much to down a brown bear. In these loads you can sometimes even get by with no crimp other than what it takes to remove the flared mouth on the case, or maybe just a touch more. The case tension does as much or more to hold things until the powder is lit than anything.

I also mentioned case tension. This is something that can, in effect change everything. If you over crimp a load you can easily release most of the tension, from the case being squashed, during that process. I believe you mentioned this with those plated bullets you were asking about not long ago. You can easily see the same thing with standard jacketed bullets when crimping into the cannalure. Especially if the cases haven't been trimmed to length. To check for proper tension with jacketed loads I usually look for the ID of the case to be around .003" or so smaller in diameter, after sizing, than the actual bullets diameter. Of course this would be using revolver straight walled cases. With auto cases which are tapered you have to also consider how deep the bullets will be seated as well to a point. Either of these also really comes into play when shooting cast. But that is a whole nuther bag of worms.

To be honest with the plated bullets you were speaking about the other day, I personally would probably relegate them to target type loads where a decent taper crimp would be sufficient to hold them under recoil of a faster type powder similar to Unique or the Universal you mentioned. It's just that without the cannalure, getting a consistent crimp which would be good enough to hold the slick sided bullet in place under a heavier recoil would be, somewhat as you have found, a pain the backside. That isn't to say it cannot be done, but it has more lumps to be worked out of the dough than should be necessary.

[loic]

I shoot and reload for 9 mm and 38 spl. I use platted bullet (xtreme or berry 124 gr for 9mm) I barely crimp as its not really needed here. Primer are win and powder is win 231. Last week I was shooting at a 10 inch target at 100 meters (just for fun) I hit it 3 times out of 16 rds and the rest was close. So accuracy can really be achieve with a pistol. A guy on the cz forum shoot 1000 and 200 yards with his pistol using a red dot and I whish I could become as good as he is. He put some video, its just amazing...