F5 Vs F75 Or T2 All Metal

[Daniel Tn]

Got home and just put the T2 on the measuring board.  Moment of truth....motion all metal. 95 sens. .58 cal minie ball = 14.5 inches loud and clear.  If you wanted to go by just a consistent whisper, you could say 15 inches.   This is on par with my buddies pre DST unit.  If I put that bad boy in BP mode and flip over to all metal mode, it gets it at 16 inches and a very nice bass thump at 14-15.  Very impressed and happy with that.  That's how it should be.  

Chase -- My first few trips to Culpeper was with the F75. I can tell ya...nothing is going to read right.  Almost every target I dug had an iron ID.  Seemed like the numbers were 11s and 13s most of the time.  I dug a breast plate just 10 inches or so deep...total iron signal til it was out of the hole.  I think I had 80 something dropped and carved bullets, 20 or so buttons, a plate, and other odds and ends like j hooks, bayonet scabbards, etc on my first hunt up there with it.  But...my buddy had a TDI and he came over to the little spot I had found and was pulling stuff left and right after I had pounded it for 2.5 days with the F75.  I had a TDI by the next hunt lol. That was my intro to pulse vs vlf.  The next hunt there (Coles Hill) I went back to that little camp to get leftovers and never left it for 3 days. I pulled over 100 minies out of it, close to 50 buttons, and another breast plate.  I never got to hunt there with a GPX.  

[Rick N. MI]

I found the T2se with dst in all metal to still be very deep. Put it in boost mode then all metal. All metal gets a boost.

[Chase Goldman]

1 hour ago, Daniel Tn said:

Got home and just put the T2 on the measuring board.  Moment of truth....motion all metal. 95 sens. .58 cal minie ball = 14.5 inches loud and clear.  If you wanted to go by just a consistent whisper, you could say 15 inches.   This is on par with my buddies pre DST unit.  If I put that bad boy in BP mode and flip over to all metal mode, it gets it at 16 inches and a very nice bass thump at 14-15.  Very impressed and happy with that.  That's how it should be.  

Chase -- My first few trips to Culpeper was with the F75. I can tell ya...nothing is going to read right.  Almost every target I dug had an iron ID.  Seemed like the numbers were 11s and 13s most of the time.  I dug a breast plate just 10 inches or so deep...total iron signal til it was out of the hole.  I think I had 80 something dropped and carved bullets, 20 or so buttons, a plate, and other odds and ends like j hooks, bayonet scabbards, etc on my first hunt up there with it.  But...my buddy had a TDI and he came over to the little spot I had found and was pulling stuff left and right after I had pounded it for 2.5 days with the F75.  I had a TDI by the next hunt lol. That was my intro to pulse vs vlf.  The next hunt there (Coles Hill) I went back to that little camp to get leftovers and never left it for 3 days. I pulled over 100 minies out of it, close to 50 buttons, and another breast plate.  I never got to hunt there with a GPX.  

Yep.  I hunt there almost exclusively with the GPX and only pull the vlf out for work in thick iron or to scan the dirt dug out of a pit, use it in wooded areas where the dirt is not as hot or simply when my shoulder wears outcfrom the GPX.  Not everyone has a PI (I wrote an article for the DIV website on why a PI is the preferred choice of Culpeper "veterans") there so I like to give advice on which of the new VLFs tend to work best in the hot stuff (and even "the classics" like the F75/T2 and MXT) if I have time I run some comparitive tests.  The hardest thing to get across to folks not used to the hot stuff is that there is a big diffrence between detection depth and ID depth on a vlf in that soil.  ID depth runs out very quickly within anywhere from 2 to 6 inches.  After that, you can hear the target but the ID Is unreliable.  So it becomes a dig it all situation.

I had success at the last DIV by taking my D2 where the GPX's dare not go.  One of our crew had pulled a couple keepers in a productive field but it was near roadside modern trash and power lines.  I decided to give it a go in another field just to switch things up a little and change my luck.  It was painful to keep pulling the 99% probable aluminum cans and canslaw, but was rewarded with a split Breast Plate and a NY Coat button that was hiding there in that relic detectorist's nightmare.

This year, trying out the Axiom...  Would like to find a new home for the GPX and my ATX backup and "rain" machine).  They have both served me well, but really want the clean ergonomics, settings simplicity, lighter weight and GPX level performance of the Axiom.

[JCR]

@GB_Amateur I am not a Civil War scholar. I do know a good bit about bullet casting & reloading and related history.

Most of the military small arms ammunition used during that period was factory made in cartridge form. Hollow base bullet & black powder charge done up together in nitrated paper. You would separate the bullet from the paper holding the powder, pour the powder down the barrel, cram the paper down the barrel, start & ram the bullet home, cap & ready to fire. That is why soldiers had cartridge boxes not powder horns & ball bags. Arms like the Spencer carbine were breach loaded with metallic(Copper) fixed ammunition.  I am not sure if any of the factory bullets were swaged at this stage. Perhaps some Union but Confederate was cast in gang moulds as far as I know, There was some casting done in camps also. Shotguns were still muzzle loaded with buck & ball and often used by Confederate Calvary and Artillery and some line troops. Casting lead was made up in "pigs" of around 20 lbs. These were hacked down with an axe for the melting pot.  I have dug one of these hacked up pigs in a Confederate camp along with an axe head with the eye split out.  This pig is not pure lead. I can tell by the color of the metal & it's hardness.

I'm not sure if any of the lead for Factory or field cast was purposely alloyed or not. Pure lead is not natural, it has to be refined. In nature it is often associated with Tin and Silver.  Tin is the normal bullet alloy with lead @ 60/1 to 40/1 for Black Powder guns. The Tin, whether added by nature or man is needed to lower the eutectic point of where the metal melts & flows.  Without this Tin, the mould won't fill out well & the bullet may have voids unless cast excessively hot.( about 800*F+)     My normal cast temp for 20/1 is about 700-710*F.

All this may be interesting to some, it certainly is to me but has nothing to do with finding a bullet with a detector. Pure lead or alloyed will TID almost exactly the same.

 

[Chase Goldman]

1 hour ago, GB_Amateur said:

Nice post Hugh, and rather a general one but that's good since not everyone has the 'background' knowledge, particularly with a specific detector model.  I think I agree with everything you said (after one readthru).  I'll try to answer what is specifically directed at my post.

Yes, your drawing is consistent with my air test measurements.  I should have done a better job (with drawings or photos) than counting simply on words which sometimes can be confusing.

My intent (there's that word again 😁) was to confirm/refute the measurements Daniel made with his F75, not to claim he made a mistaken measurement but rather to ask "do all of the DST models of the F75 give weaker air test performances than the original non-DST models?"  I was definitely not implying that my results (or his) would carry over to actual in-ground targets.  (You knew this but maybe others didn't....)  Also, since he used a Civil War(CW) bullet I tried as close as possible to use a similar target, although that alone was a 'weakness' of my test.  At least mine was smaller, not larger, but I think it's likely the composition is different.   BTW, no one has yet answered my question about CW bullet composition.  JCR talked about bullets in general, though.  During a Google search I did see a claim that CW bullets were pure lead, but that was from a metal detecting forum post (not our beloved DetectorProspector.com forum) so I was unsure of its veracity.

My F75 is a great backup detector to the Minelab Equinox 800 and soon it will be 3rd in line, but still not going anywhere.  I've always found it deep, but it's not (in my experience) very good at ID'ing coins nearly as deep in-ground as the Eqx 800.  Part of that is surely its single frequency (13 kHz) vs. the Eqx multifrequency (~5-6 kHz combined with ~38 kHz, with maybe one other freq in-between).  Been said before and worth saying again -- it (ditto its older cousin, Teknetics T2) is still the best ergonomic design out there that I'm aware of.  (Now I've started another detector war....  🙄)

JCR thoroughly answered your question on bullet composition.   Typical caliber was .58.  There were also .69's and .54's and carbines were typically .52 but some were in smaller caliber.  Pistols were .44 or .45 or smaller.  Actual bullet ODs varied by type.  The objective was to be able to easily push the bullet down through the barrel rifling after inserting the gunpowder, so the unfired diameter was typically less than .58.  A conical cavity at the base of most minies would expand upon ignition and engage the barrel rifling.  "Cleaner" bullets had zinc inserts in the base that would expand upon firing to scrape gunpowder residue that would build up on the rifling of the barrel.

The main point I wanted to make was that translating air test results to actual in-ground performance was always tricky, but in situations where depth performance is degraded such as when mineralization is present (hot dirt) then the depth differences between the tested configurations shrink or get compressed typically in proportion the air test measurements.

Thanks for the clarifications and posting your results.

[JCR]

2 hours ago, Chase Goldman said:

Daniel,

Thanks greatly for the info on that 12" coil.  First person I've heard of that has actually used it!  I was looking at it mainly for weight and reduced footprint in hot dirt.  I have a 13" Ultimate on the F75 right now.  I will look into the Super Fly, and thanks greatly for the offer to borrow and try that new coil.  I'll PM you if I decide to try it out after all.  I think I will bring the F75 to Culpeper at least with the stock and bake it off against the D2, Nox 900, and Legend on Minies.  Right now focusing on getting half way proficient on the Axiom b4 the trips down.

I will look forward to your Culpepper report, especially how the Axiom and Legend perform. I am tempted by the Axiom and have good confidence in the Legend for my hot sites. Maybe a observation by you on how these stack up against the Tarsacci.

@Daniel Tnhas inspired me to re test my Vista X, Tarsacci & Legend with their big coils on a .58 cal Minie.  Just an air test but it may give me some guidance/confidence on a couple of low mineral deep sand sites that should have more "old" there than what I have found.

[JCR]

I edited my earlier treatise to clarify & correct after reading Chase's post. I really shouldn't be posting off the top of my head when I'm busy, supposedly with work.🙃

[Mark Gillespie]

On 2/28/2023 at 2:56 PM, Daniel Tn said:

Something I had forgotten about since last having an F75:  the newer DST model F75s have been neutered from what made them great.  They have a VERY weak all metal mode now.  To get a good one, you'll have to find one that hasn't been updated and is a non DST model.  Just an example for you...the F75 I recently traded for is a DST model. With it at 99 sensitivity, it will only AIR TEST a .58 cal Minie ball out to 9.5-10 inches in all metal.  And you have to really be listening to hear it. By comparison, we tested my buddys original non updated F75 on the same minie ball and his unit sounds like it has an audio boost enabled in all metal and is much more powerful.  We couldn't get his to 99 sens due to chatter but with it on 80, it was calm and could detect that minie out to 14 inches.  Yes, that's a 4 inch difference.  Whereas the newer one was weak and barely hearable at 10 inches...his was a "no doubt about it" signal at 10...very pronounced.  We could actually turn his sensitivity down to 60 and 70 and still get better distance than the neutered F75 at 99 sens.  I traded a CZ70 Pro with George here on the forum for a T2. I'm hoping like crazy that it's a non DST model lol. Or at least isn't as badly neutered as the F75 I have.  

I have the Pro Arc which is the F75 LTD with a different face plate.  I get a consistent 15" air test on a US nickel with both the DST settings.   All metal is absolutely awesome in the boost mode.  I have a few civil war bullets I might try tomorrow. 

[Badger-NH]

9 hours ago, Mark Gillespie said:

I have the Pro Arc which is the F75 LTD with a different face plate.  I get a consistent 15" air test on a US nickel with both the DST settings.   All metal is absolutely awesome in the boost mode.  I have a few civil war bullets I might try tomorrow. 

There is a big difference between air testing and ground testing. Try burying some targets at precise depths and see how it does. Make sure the ground is free of metal and hot rocks.

My non-DST T2 SE easily went an inch deeper on a silver dime and two inches deeper on a silver quarter than my F75 DST in mild soil. Both using the 15" x 10" SEF coil.

 

[Mark Gillespie]

Exactly, but I wanted to state my machine does well regardless of the DST settings.  One has less chatter than the other.  Of course I'm using the stock 11" DD coil.  High minerals in the ground will cause many different kinds of target anomalies.  For me, high minerals will pull down the target ID and audio and yes times all the way into the iron range.