Cant go wrong with Total Seal conventional rings . Their Gapless wasn't that great but they did work . We Used the tool steel top , and a Napier second . Also used the Rikkens. They are good too.

300 hours on hellfire rings?

i have had great results with the 0 gap top rings.

Not a builder but I've built enough motors. I've had good luck with Mahle with the stroker pistons. Never had a failure with Hastings either.

A good test would be , comparing ring seal at break in, and at 300 hours with a blowby meter.

Its been pretty much proven that low leakdown % isnt telling the story about how well a ring is sealing. Ive seen friends with total seal gapless rings push the dipsticks out, blow oil out the breathers, while their gapless ring still was showing like 5% leakdown on the gauge.

maybe time for a new leak gauge.through the years i have done a lot of lead down tests and the readings pretty much told the story.i have a snap on tester that i bought 20 years ago,it is a high quality gauge and i believe it is pretty acurate.i have seen the cheeper gauges that were pretty much useless.imo,if you have an engine that is blowing oil from the breathers and pushing the dip stick out their is no need to do a leak test as it is obviously leaking past the rings.

also want to mention that an engine with an overly rich tune up can ruin the ring seal on any brand of rings.often a person will blame the brand or type of ring for a failure when the tune up was the culprit.

FWIW..
I used a Total Seal AP conventional set in my build..




Don't have it running in the boat yet but ran fine on the dyno..

Had a little bit of visible blowby out the breathers but I do have fairly wide end gaps for the blower..

Putting 100psi in a cold cylinder, with a stationary piston, with a ring that has zero gap, vs a ring with a gap, naturally is going to show different leakdown rates. Its like blowing thru a straw with no hole on the end, or a small hole on the end.

However, it has nothing to do with how the ring is sealing when there is 1500 psi in the cylinder, the piston traveling at 4000ft per minute, psi between the rings keeping the ring seated against the land, and so on.

Even the most expensive big power engines with big blowers , sometimes run puke tanks on them to catch the oil from the breathers.

My engines showed 15 percent leakdown when new, and still showed 15-18 percent leakage past the rings. Some guys would say thats too much. I dont care about the gauges reading. What matters, is that i have ran my boat over 400 miles, most of the time between 3/4 and wide open throttle, and didnt add a drop pf oil to the crankcase, nor had anything coming from the breathers. Shortly after that trip, i went on a fun run, where i ran 60 miles, where the engines never saw below 5,000 rpm, and spent most of the time at 5500 rpm. Again, no lost oil.

My engines have ran for the past 4 seasons , without a hiccup. But , ive always monitored air fuel ratio, and maintained them. I came off the dyno in 2012, with 82/92 jets . In the boat, at wide open, air fuel ratio was in the mid 12s, and dangerously lean in the high 13s at part throttle. I changed to 88/96 jets, gained speed, and now have a safer afr. Like you said though, a poor tune can kill rings and cylinder finish in a hurry. First thing ill be doing from here on out, is first time the engines come off the dyno and go in the boat, the afr will be on before i even get on plane .

After 100 plus hours at 800hp, the cylinders look like they were honed yesterday. Certainly not gonna look like that with a bad fuel tune.

https://youtu.be/bFFFqZrc9Qo Good info there on leakage tests