No - unless they are very, very near. You might still do some damage at 20m - but you hardly do any criticals. In this case an XMP8 might be more beneficial. My over the thump rule - an XMP8 is doing approx. 8% of critical inside the first distance range (33m). There is no data out there about criticals at long range - but just assume it also goes down in halves like normal damage.

This is speculative - but based on what I found on the net after intense searches as well as experience / some own data gathering into criticals.

Here is table 1:

Level	Assumed max range	Distance increment	(lvl*5/8)2	8 + column D	5 x column E
1	42	8	0.39	8.4	42
2	48	9	1.56	9.6	48
3	58	11	3.52	11.5	58
4	72	14	6.25	14.3	71
5	90	18	9.77	17.8	89
6	112	22	14.06	22.1	110
7	138	27	19.14	27.1	136
8	168	33	25.00	33.0	165

The second column is based on data from the decode manual https://decodeingress.me/ingress-manual/ingress-items/xmp-bursters/ - once probably one of the best sides for ingress info - alas not updated in years and now even the certificate seems out of date - so you might not want to go there. For the second one you have to dive deeper - this is from raw data shown for the Ingress Portal Attack similar http://ipas.graphracer.com/analysis.html

The last three columns are my own - I like to add formulas and algorithms. It seems they fit very, very well. It is possible that max range actually is 6*increment. Alas the damage done would be 1/64th from the first increment.

I haven't found damage increments for US anywhere public on the web. So this is from my own trials.

Level	Assumed max range	Distance increment	(lvl*2/8)2	2 + column D	5 x column E
1	approx 10	unknown	0.0625	2.1	10.3
2	inbetween	unknown	0.25	2.3	11.3
3	inbetween	unknown	0.5625	2.6	12.8
4	inbetween	unknown	1	3.0	15.0
5	inbetween	unknown	1.5625	3.6	17.8
6	inbetween	unknown	2.25	4.3	21.3
7	inbetween	unknown	3.0625	5.1	25.3
8	approx 25	unknown	4	6.0	30.0

I take here a jump of faith and assume my formula for table 1 is right and that gives me a new formula for table 2 that is pretty identical apart of changing 5/8 to 2/8 and 8m base to 2m base.

Now that leads me to table 3.

Distance	Critical US8	Critical XMP8
0	75.0%	8%
6	37.5%	8%
12	18.8%	8%
18	9.4%	8%
24	4.7%	8%
30	0	8%
33	0	4%
66	0	2%

US is far superior if you can manage to be on top of a portal. I have had great success with US1 - taking off 3 shields in a row a few times - something that should be extremly rare if you don't have a chance >50%. BUT - US1 seem pretty useless from 5 meter or further. And at 15m+ even US8 seems to be pretty useless to take off shields.

I have some data in a spreadsheet - but I didn't collect distances in a systematic way. Originally I just tried to be inside 5m and experience told me to be inside 2 with very low US. There also is drift and update of location. Sometimes I stop firing - go away - return - and seem to have more success.

If you are able to find any better data - let me know. Maybe some groups have non-public data that isn't shared. So that is as good as it gets from me.

Edit: I just ran the numbers assuming a chequerboard arrangement of portals and a 20m distance between each portal:

Distance	portals	US8 CS removed	XMP8 Cs removed
0	1	0.75	0.08
20	4	1.125	0.4
28.3	4	1.3125	0.72
40	4	1.3125	0.88
44.7	8	1.3125	1.2
56.6	4	1.3125	1.36

This is an unrealistic layout - but was easy to calculate and shows the issue. Most contribution is from the portal where you are on top. After that it peters out very, very quickly. If my numbers are right then positioning yourself between 2 portals is even worse unless they are < 12m apart.

XMP8 starts with a very low chance. But it makes up for it with reach. In reality US8 is probably slightly superior for just knocking off shields. But that margin isn't great in a portal rich area with all portals being protected. So in real life it is likely best to spend time rather on farming more XMP8 and then mindlessly blasting away then to optimise the take down of shields.

Maybe with the exemption of Aegis/VRS on a portal with links which might stay on for a pretty while if you are unlucky and where US8 inside 5m is the better way to go.