Designing a projectile which can be used successfully in a rifle has been a huge challenge, and the bullets have been in the works for some time now. 

We've tested projectiles for several popular firearms and cartridges, from the AR-15 in .223/5.56 to the gamut of .30 caliber and .308/7.62x51 NATO rifles available. 

Not only do we need to prevent leading of the bore and excessive smoking, but the projectiles need to be accurate at range. They also need to have all these characteristics, while operating at the high pressures needed to cycle a semi-automatic action. Shooting a bolt-action rifle simplifies things considerably, you can load them as slow or as fast as you'd like, and pick whichever load gives the best accuracy.

Several pieces of information became apparent during testing:

1. The range of powders and charge weights that can be used with success is narrower than what can be used with jacketed bullets.
   
2. The bullets can be fired at very high speeds (3,000+ fps) without leading, but the coating begins to smoke A LOT when they are pushed this fast.
   
3. The top speed at which these projectiles yield the best accuracy is between 2,000 and 2,300 fps. This seems to be the "sweet spot."
   

Because of #3, we began offering heavy .30 caliber bullets in the 200-220gr range. If the speed is capped at 2,300fps, the heavier bullets offer more momentum during flight, and easily generate enough pressure in the chamber and bore to cycle the action on a semi-automatic gun when using standard load data for a jacketed bullet. 

The powders I've had the best luck with in this testing have been Varget and H4895, using data from an equivalent weight jacketed bullet, but sticking to the low end of charge weights. This range of powders appears to be in the burn-rate sweet spot, but of course finding a variety of powders to test with has been an ordeal for the last couple of years!

I'm no expert rifle shooter, but the best load (so far!) with our polymer coated bullets groups well enough that I feel 100% confident using it for short-mid range targets in a 3-gun match. I'm sure that once more shooters begin adopting these bullets and fine-tuning their pet loads, we'll see some incredibly accurate shooting! 

The load that shoots best out of my PTR-91 (a .308 / 7.62x51 NATO cartridge) is as follows:
Unsorted, once-fired LC 7.62x51 brass.
Brass trimmed to minimum SAAMI spec
Neck expanded using Lyman Neck Expander (M-Die)
CCI Large Rifle Primers
Varget: 38.0 gr.
EM 200gr. Polycoated Bullet, sized to .311" (http://www.egglestonmunitions.com/rifle.html)
C.O.A.L of 2.775" 

The load has gentle recoil compared to factory NATO ammo, gives 100% reliable feeding and ejection, and groups well. 

This might be a good starting point for other folks looking to start developing their own loads!

We  hear this question a lot, "Will these bullets work in a Glock?" And while the short answer is YES, and we even have a brief answer listed in our 'Frequently Asked Questions,' this question requires a slightly longer answer.

The question comes up because of information (or misinformation?) about using cast lead bullets in barrels with polygonal rifling, and this stuff has been floating around on the web and in shooting circles for decades. 

It also doesn't just affect Glocks, there are several manufacturers who use polygonal rifling, including H&K, CZ, Bersa, and others, but we rarely hear anything about them.

There are two distinct issues that I've heard regarding this topic: Excessive leading of the bore and poor accuracy. The issue of leading has been shown to generally be a myth. No matter what kind of rifling you use, if your bullet and load does not match your bore diameter well, you will get leading. If you use a fast, hot burning powder, or push the bullets very fast, you can get leading. It's been demonstrated by hundreds of competitive Glock shooters who run (properly loaded) hard-cast lead bullets that leading can be reduced or eliminated, so that just leaves the second issue: Accuracy.

Unlike the misinformation about leading, there IS some merit to the issue of accuracy in polygonal rifling. Traditionally cut rifling has very sharp corners on the lands which really bite into the surface of the bullet and impart spin. Polygonal rifling features more obtuse angles in comparison (think gentle rolling hills & valleys), and while this works great on jacketed or plated bullets, the relatively soft hard-cast lead bullets do not 'bite' as well on these. 

Because of this, it becomes much more critical that your choice of bullet fits the bore diameter perfectly, so that the body of the projectile fills the grooves of the rifling and spins effectively (This is one of the reasons why we offer multiple sizing diameters on many of our bullets). 

With our polymer coated bullets, suddenly this isn't as big of an issue, since the surface of the bullet becomes much tougher, more like a plated or jacketed bullet. These bullets will engage the rifling effectively, even if they are slightly undersized. However, for the best accuracy, measure your bore and pick the bullet which fits perfectly or is .001" over the size of the max bore diameter. Alternatively, if you don't want to slug your bore and measure, we offer sample packs in multiple diameters so you can test fire them and pick whichever one groups best!