The Magazines, Ammo & First Range Trip for the New 10mm TRP Operator

This post is continuing on the story of my newly purchased Springfield Armory TRP Operator 10mm Longslide. I’m going to touch on three topics – the initial mags, ammo and my first trip to the range.

The Magazines

The pistol comes with two 8-round magazines that flush fit with the bottom of the grip. My experience with factory mags is mixed so I bought four Wilson Combat 47NX magazines to use as well plus they hold 9 rounds and have a bumper on the bottom.

On the left is one of the two 8-round magazine that Springfield Armory supplied with the pistol. On the right is one of the four Wilson Combat 47NX 9-round magazines I bought.

Left is the factory mag and on the right is the Wilson. Note the slightly different shape to the magazine body at the top. Interestingly, both followers are stamped with the same patent number. The followers are identical but not the bodies or the floor plates.

I tried a factory magazine with one of the S&B 180gr FMJ rounds I bought and it immediately jammed on the first test, and the second and the third. Okay, I really wasn’t surprised given past poor experiences and tried one of the Wilsons. The round went right in. I thought that fixed the problem and we’ll come back to that later when we discuss the range.

The Ammunition

With my Rock Ultra and Bruin, S&B 180 grain FMJ proved to be a very decent range ammo so I bought a few hundred rounds of it to break in the TRP.

In the 10mm community, Underwood has a great reputation and I had also used it with both of my previous 10mms. This time though, I bought 5 boxes of 220gr hard cast for bears and 4 boxes of 200gr XTP to try out.

From left to right: Underwood 220gr hard cast (the bullet is colored red and easy to spot), Underwood 200gr XTP HP and last, S&B 180gr FMJ.

So here is a side-by-side in the same order – Underwood 220gr Hardcast, Underwood 200gr XTP and S&B 180gr FMJ.

The hardcast comes in at 220 grains and the bullet is a “Hi-Tek Coated Hard Cast Flat Nose” and the Brinell Hardness Number (BHN) is 41. That puts it somewhere between copper at 35 BHN and Hardened 6060 Aluminum at 75BHN. Pure lead comes is at 5 BHN. In short, you’d expect it to penetrate without mushrooming easily – which is what I would want for a bear’s skull for example. The round pushing the bullet 1200 FPS and 703 ft/lbs at the muzzle makes sure it gets delivered hard.

The 200 grain XTP was what the vendor had in stock at the time. I like XTP bullets in general as they perform well in terms of mushrooming so this is not something I would use on a bear but two legged predators maybe. Underwood reports that the muzzle velocity is 1,250 FPS with 694 ft/lbs.

The S&B 180 grain FMJ is for the range. In the past I found it affordable, reliable and accurate enough for practice. S&B USA reports that it’s exiting the muzzle at 1,165 FPS with 544 ft/lbs of energy.

A Quick Cleaning and Lubrication

I ran a couple of 10mm RamRodz down the bore to clean out the accumulated gunk from the factory and travel. I then applied Superlube to the frame rails and other lubrication points on the pistol.

The First Range Experience

The weather was perfect for going to the range and both Niko and I commented that as we lugged firearms, ammo, targets and what have you down the shooting lane we planned to use.

Getting ready to shoot. Ignore the MagLula – we had some Polymer80s and SIGs to shoot after the TRP.

First up for testing was the TRP operator. We loaded the Wilson Combat mags up with the S&B ammo, loaded the first round, fired and it jammed. Well crud. It was jamming hard too – the bullet was hitting the top of the chamber during feeding but not rotating enough to then go the rest of the way forward. After a few of these we noticed that the transition point between the feed ramp and the chamber was actually indenting the brass enough to cause a notch and stop the round hard. So much for the S&B at that point.

We then switched to the hard cast and the TRP relatively liked that. It fired a lot more with fewer jams. What we noticed was that the angle on the hard cast bullet seemed to be such that it helped the round to properly chamber most of the time. So, we shot about 20 rounds in total and decided to move on to the 200gr HP.

Wow – the Underwood 200gr XTP load was jam city. I could not get them to feed at all. So, disappointed, we stopped shooting the TRP and put it away. In looking at the cases, I was betting that I needed to slightly bevel the transition point and polish both the ramp and chamber. Doing that will be the topic of our next post — and yes, it did make a world of difference.

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