First of all, the amount of crimp on reloads: load a few and push the bullet end into a scale(for bathrooms) it shouldn't move while being pushed to about 15 pounds. As for gas checks they do help stop the leading of the bore but, this can be reduced by using the formula for hardness, the faster the reload the harder the bullets need to be, here's what the gunsmith on the Ruger forum has to say about this situation:
To expand on this a little more, let me try to explain about obturation. When pressure is applied to the base of a lead bullet, the bullet base will want to expand in diameter to fit the size of the "container". This is called "bumping up". In a revolver, this would first be the free bore or cylinder throat. As pressure continues to push the bullet, the forcing cone will act like a sizing die and reduce the diameter of the bullet to fit tightly in the bore.
Before a bullet can obturate properly, there are several conditions that must be met. First, you need to match chamber pressure to the hardness of the bullet. The harder the bullet, the more pressure it needs to obturate. Next you must have a throat that is slightly larger in diameter than the bullet and bore. If these conditions are met, the bullet will change shapes a couple times without shedding any material (lead fouling).
The problem with hard cast bullets is they require a very high chamber pressure before they will obturate. In many cases, chamber pressure would exceed maximum before the bullet would bump up. There is a formula that states: lead hardness (in Brinnel) times 1440 equals chamber pressure (in psi) for proper obturation. Most hard cast "store bought" bullets have a Brinnel hardness of 20-24. If you do the math, a 38 Special load with a 20 BHN would require 20x1440 or 28,800 psi. The SAAMI max pressure for a 38 Special is 17,000 psi. As you can see, a hard cast bullet in a 38 Special would never reach obturation without exceeding max chamber pressure.
If you use a softer swaged bullet with a BHN of 10, you can easily get obturation (14,400 psi) and stay well under max chamber pressure.
If softer bullets are driven too hard, they too will smear and foul. So the secret is to use the proper burn rate powder and the right charge weight to stay within the obturation range. Here's where the fun begins. Most of us don't have a Brinnel hardness tester nor do we have pressure measuring equipment. This means we have to know a little about our components. If you use hard cast bullets, you must use a healthy charge of fast burning powder to get good results (could be dangerous). The better solution is to use soft bullets and a modest charge of medium burn rate powder (much safer).
Accuracy, and fouling always track with obturation. The better a bullet obturates, the better accuracy will be and fouling will be minimal.
